diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8215f07..707a25e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,14 @@
 
 ## [Unreleased]
 
+- ✨ — IPv4/IPv6 choice for checks, and choice for a dual-stack check (#69)
+- ⚡ — Mutualize check requests (#68)
+- ✨ — Ability to delay notification after X failures (#71)
+- 🐛 — Fix bug when changing IP version not removing tasks (#72)
+- ✨ — Allow to specify form data and headers for checks (#70)
+- 🚸 — Add a long expiration date on auto-refresh cookies
+- 🗃️ — Use bigint type for results id column in PostgreSQL (#73)
+
 ## 0.6.1
 
 Date: 2024-11-28
diff --git a/argos/agent.py b/argos/agent.py
index d791641..195ffdc 100644
--- a/argos/agent.py
+++ b/argos/agent.py
@@ -6,6 +6,7 @@ import asyncio
 import json
 import logging
 import socket
+from hashlib import md5
 from time import sleep
 from typing import List
 
@@ -33,7 +34,7 @@ def log_failure(retry_state):
     )
 
 
-class ArgosAgent:
+class ArgosAgent:  # pylint: disable-msg=too-many-instance-attributes
     """The Argos agent is responsible for running the checks and reporting the results."""
 
     def __init__(self, server: str, auth: str, max_tasks: int, wait_time: int):
@@ -41,18 +42,33 @@ class ArgosAgent:
         self.max_tasks = max_tasks
         self.wait_time = wait_time
         self.auth = auth
-        self._http_client = None
+        self._http_client: httpx.AsyncClient | None = None
+        self._http_client_v4: httpx.AsyncClient | None = None
+        self._http_client_v6: httpx.AsyncClient | None = None
+        self._res_cache: dict[str, httpx.Response] = {}
 
         self.agent_id = socket.gethostname()
 
     @retry(after=log_failure, wait=wait_random(min=1, max=2))
     async def run(self):
-        headers = {
+        auth_header = {
             "Authorization": f"Bearer {self.auth}",
+            "User-Agent": f"Argos Panoptes agent {VERSION}",
+        }
+        self._http_client = httpx.AsyncClient(headers=auth_header)
+
+        ua_header = {
             "User-Agent": f"Argos Panoptes {VERSION} "
             "(about: https://argos-monitoring.framasoft.org/)",
         }
-        self._http_client = httpx.AsyncClient(headers=headers)
+        self._http_client_v4 = httpx.AsyncClient(
+            headers=ua_header,
+            transport=httpx.AsyncHTTPTransport(local_address="0.0.0.0"),
+        )
+        self._http_client_v6 = httpx.AsyncClient(
+            headers=ua_header, transport=httpx.AsyncHTTPTransport(local_address="::")
+        )
+
         logger.info("Running agent against %s", self.server)
         async with self._http_client:
             while "forever":
@@ -61,27 +77,71 @@ class ArgosAgent:
                     logger.info("Waiting %i seconds before next retry", self.wait_time)
                     await asyncio.sleep(self.wait_time)
 
+    async def _do_request(self, group: str, details: dict):
+        headers = {}
+        if details["request_data"] is not None:
+            request_data = json.loads(details["request_data"])
+            if request_data["headers"] is not None:
+                headers = request_data["headers"]
+
+        if details["ip_version"] == "4":
+            http_client = self._http_client_v4
+        else:
+            http_client = self._http_client_v6
+        try:
+            if details["request_data"] is None or request_data["data"] is None:
+                response = await http_client.request(  # type: ignore[union-attr]
+                    method=details["method"],
+                    url=details["url"],
+                    headers=headers,
+                    timeout=60,
+                )
+            elif request_data["json"]:
+                response = await http_client.request(  # type: ignore[union-attr]
+                    method=details["method"],
+                    url=details["url"],
+                    headers=headers,
+                    json=request_data["data"],
+                    timeout=60,
+                )
+            else:
+                response = await http_client.request(  # type: ignore[union-attr]
+                    method=details["method"],
+                    url=details["url"],
+                    headers=headers,
+                    data=request_data["data"],
+                    timeout=60,
+                )
+        except httpx.ReadError:
+            sleep(1)
+            if details["request_data"] is None or request_data["data"] is None:
+                response = await http_client.request(  # type: ignore[union-attr]
+                    method=details["method"], url=details["url"], timeout=60
+                )
+            elif request_data["json"]:
+                response = await http_client.request(  # type: ignore[union-attr]
+                    method=details["method"],
+                    url=details["url"],
+                    json=request_data["data"],
+                    timeout=60,
+                )
+            else:
+                response = await http_client.request(  # type: ignore[union-attr]
+                    method=details["method"],
+                    url=details["url"],
+                    data=request_data["data"],
+                    timeout=60,
+                )
+
+        self._res_cache[group] = response
+
     async def _complete_task(self, _task: dict) -> AgentResult:
         try:
             task = Task(**_task)
 
-            url = task.url
-            if task.check == "http-to-https":
-                url = str(httpx.URL(task.url).copy_with(scheme="http"))
-
-            try:
-                response = await self._http_client.request(  # type: ignore[attr-defined]
-                    method=task.method, url=url, timeout=60
-                )
-            except httpx.ReadError:
-                sleep(1)
-                response = await self._http_client.request(  # type: ignore[attr-defined]
-                    method=task.method, url=url, timeout=60
-                )
-
             check_class = get_registered_check(task.check)
             check = check_class(task)
-            result = await check.run(response)
+            result = await check.run(self._res_cache[task.task_group])
             status = result.status
             context = result.context
 
@@ -100,12 +160,45 @@ class ArgosAgent:
         )
 
         if response.status_code == httpx.codes.OK:
-            # XXX Maybe we want to group the tests by URL ? (to issue one request per URL)
             data = response.json()
             logger.info("Received %i tasks from the server", len(data))
 
+            req_groups = {}
+            _tasks = []
+            for _task in data:
+                task = Task(**_task)
+
+                url = task.url
+                group = task.task_group
+
+                if task.check == "http-to-https":
+                    data = task.request_data
+                    if data is None:
+                        data = ""
+                    url = str(httpx.URL(task.url).copy_with(scheme="http"))
+                    group = (
+                        f"{task.method}-{task.ip_version}-{url}-"
+                        f"{md5(data.encode()).hexdigest()}"
+                    )
+                    _task["task_group"] = group
+
+                req_groups[group] = {
+                    "url": url,
+                    "ip_version": task.ip_version,
+                    "method": task.method,
+                    "request_data": task.request_data,
+                }
+                _tasks.append(_task)
+
+            requests = []
+            for group, details in req_groups.items():
+                requests.append(self._do_request(group, details))
+
+            if requests:
+                await asyncio.gather(*requests)
+
             tasks = []
-            for task in data:
+            for task in _tasks:
                 tasks.append(self._complete_task(task))
 
             if tasks:
diff --git a/argos/config-example.yaml b/argos/config-example.yaml
index b20c48f..5508bff 100644
--- a/argos/config-example.yaml
+++ b/argos/config-example.yaml
@@ -64,6 +64,23 @@ general:
   # For ex., to re-try a check one minute after a failure:
   # recheck_delay: "1m"
 
+  # Default setting for notifications delay.
+  # Say you want to be warned right after a failure on a check: set it to 0
+  # Say you want a second failure on the check before being warned,
+  # to avoid network hiccups: set it to 1
+  # Can be superseeded in domain configuration
+  # If not present, default is 0
+  # retry_before_notification: 0
+
+  # Defaults settings for IPv4/IPv6
+  # Can be superseeded in domain configuration.
+  # By default, Argos will check both IPv4 and IPv6 addresses of a domain
+  # (i.e. by default, both `ipv4` and `ipv6` are set to true).
+  # To disable the IPv4 check of domains:
+  # ipv4: false
+  # To disable the IPv6 check of domains:
+  # ipv6: false
+
   # Which way do you want to be warned when a check goes to that severity?
   # "local" emits a message in the server log
   # You’ll need to configure mail, gotify or apprise below to be able to use
@@ -134,6 +151,8 @@ ssl:
 #
 websites:
   - domain: "https://mypads.example.org"
+    # Wait for a second failure before sending notification
+    retry_before_notification: 1
     paths:
       - path: "/mypads/"
         # Specify the method of the HTTP request
@@ -171,6 +190,17 @@ websites:
               - 302
               - 307
       - path: "/admin/"
+        methode: "POST"
+        # Send form data in the request
+        request_data:
+          data:
+            login: "admin"
+            password: "my-password"
+          # To send data as JSON (optional, default is false):
+          is_json: true
+          # To send additional headers
+          headers:
+            Authorization: "Bearer foo-bar-baz"
         checks:
           # Check that the return HTTP status is one of those
           # Similar to status-is, verify that you don’t mistyped it!
@@ -213,6 +243,8 @@ websites:
   - domain: "https://munin.example.org"
     frequency: "20m"
     recheck_delay: "5m"
+    # Let’s say it’s an IPv6 only web site
+    ipv4: false
     paths:
       - path: "/"
         checks:
diff --git a/argos/schemas/config.py b/argos/schemas/config.py
index 13119b0..1baa7ed 100644
--- a/argos/schemas/config.py
+++ b/argos/schemas/config.py
@@ -5,7 +5,7 @@ For database models, see argos.server.models.
 
 import json
 
-from typing import Dict, List, Literal, Tuple
+from typing import Any, Dict, List, Literal, Tuple
 
 from durations_nlp import Duration
 from pydantic import (
@@ -18,7 +18,7 @@ from pydantic import (
     PositiveInt,
     field_validator,
 )
-from pydantic.functional_validators import BeforeValidator
+from pydantic.functional_validators import AfterValidator, BeforeValidator
 from pydantic.networks import UrlConstraints
 from pydantic_core import Url
 from typing_extensions import Annotated
@@ -104,9 +104,26 @@ def parse_checks(value):
         return (name, expected)
 
 
+def parse_request_data(value):
+    """Turn form or JSON data into JSON string"""
+
+    return json.dumps(
+        {"data": value.data, "json": value.is_json, "headers": value.headers}
+    )
+
+
+class RequestData(BaseModel):
+    data: Any = None
+    is_json: bool = False
+    headers: Dict[str, str] | None = None
+
+
 class WebsitePath(BaseModel):
     path: str
     method: Method = "GET"
+    request_data: Annotated[
+        RequestData, AfterValidator(parse_request_data)
+    ] | None = None
     checks: List[
         Annotated[
             Tuple[str, str],
@@ -117,8 +134,11 @@ class WebsitePath(BaseModel):
 
 class Website(BaseModel):
     domain: HttpUrl
+    ipv4: bool | None = None
+    ipv6: bool | None = None
     frequency: float | None = None
     recheck_delay: float | None = None
+    retry_before_notification: int | None = None
     paths: List[WebsitePath]
 
     @field_validator("frequency", mode="before")
@@ -204,6 +224,9 @@ class General(BaseModel):
     ldap: LdapSettings | None = None
     frequency: float
     recheck_delay: float | None = None
+    retry_before_notification: int = 0
+    ipv4: bool = True
+    ipv6: bool = True
     root_path: str = ""
     alerts: Alert
     mail: Mail | None = None
diff --git a/argos/schemas/models.py b/argos/schemas/models.py
index a4a37c2..ed1bc20 100644
--- a/argos/schemas/models.py
+++ b/argos/schemas/models.py
@@ -8,7 +8,7 @@ from typing import Literal
 
 from pydantic import BaseModel, ConfigDict
 
-from argos.schemas.utils import Method
+from argos.schemas.utils import IPVersion, Method
 
 # XXX Refactor using SQLModel to avoid duplication of model data
 
@@ -19,9 +19,14 @@ class Task(BaseModel):
     id: int
     url: str
     domain: str
+    ip_version: IPVersion
     check: str
     method: Method
+    request_data: str | None
     expected: str
+    task_group: str
+    retry_before_notification: int
+    contiguous_failures: int
     selected_at: datetime | None
     selected_by: str | None
 
@@ -31,7 +36,8 @@ class Task(BaseModel):
         task_id = self.id
         url = self.url
         check = self.check
-        return f"Task ({task_id}): {url} - {check}"
+        ip_version = self.ip_version
+        return f"Task ({task_id}): {url} (IPv{ip_version}) - {check}"
 
 
 class SerializableException(BaseModel):
diff --git a/argos/schemas/utils.py b/argos/schemas/utils.py
index 05d716a..a160ee1 100644
--- a/argos/schemas/utils.py
+++ b/argos/schemas/utils.py
@@ -1,6 +1,8 @@
 from typing import Literal
 
 
+IPVersion = Literal["4", "6"]
+
 Method = Literal[
     "GET", "HEAD", "POST", "OPTIONS", "CONNECT", "TRACE", "PUT", "PATCH", "DELETE"
 ]
diff --git a/argos/server/alerting.py b/argos/server/alerting.py
index 4c82a9b..1145053 100644
--- a/argos/server/alerting.py
+++ b/argos/server/alerting.py
@@ -11,6 +11,55 @@ import httpx
 from argos.checks.base import Severity
 from argos.logging import logger
 from argos.schemas.config import Config, Mail, GotifyUrl
+from argos.server.models import Task
+
+
+def need_alert(
+    last_severity: str, last_severity_update, severity: str, status: str, task: Task
+) -> bool:
+    ## Create alert… or not!
+    send_notif = False
+    # Severity has changed, and no retry before notification
+    if last_severity != severity and task.retry_before_notification == 0:
+        send_notif = True
+    # Seems to be a first check: create a notification
+    elif last_severity != severity and last_severity_update is None:
+        send_notif = True
+        # As we created a notification, avoid resending it on a
+        # future failure
+        if status != "success":
+            task.contiguous_failures = task.retry_before_notification
+    # We need retry before notification, so the severity may not have changed
+    # since last check
+    elif task.retry_before_notification != 0:
+        # If we got a success, and we already have created a notification:
+        # create notification of success immediately
+        if (
+            status == "success"
+            and task.contiguous_failures >= task.retry_before_notification
+        ):
+            send_notif = True
+            task.contiguous_failures = 0
+        # The status is not a success
+        elif status != "success":
+            # This is a new failure
+            task.contiguous_failures += 1
+            # Severity has changed, but not to success, that’s odd:
+            # create a notification
+            if (
+                last_severity not in ("ok", severity)
+                and last_severity_update is not None
+            ):
+                send_notif = True
+                # As we created a notification, avoid resending it on a
+                # future failure
+                task.contiguous_failures = task.retry_before_notification
+            # Severity has not changed, but there has been enough failures
+            # to create a notification
+            elif task.retry_before_notification == task.contiguous_failures:
+                send_notif = True
+
+    return send_notif
 
 
 def get_icon_from_severity(severity: str) -> str:
@@ -74,9 +123,9 @@ def notify_with_apprise(  # pylint: disable-msg=too-many-positional-arguments
         apobj.add(channel)
 
     icon = get_icon_from_severity(severity)
-    title = f"[Argos] {icon} {urlparse(task.url).netloc}: status {severity}"
+    title = f"[Argos] {icon} {urlparse(task.url).netloc} (IPv{task.ip_version}): status {severity}"
     msg = f"""\
-URL:    {task.url}
+URL:    {task.url} (IPv{task.ip_version})
 Check:  {task.check}
 Status: {severity}
 Time:   {result.submitted_at}
@@ -97,7 +146,7 @@ def notify_by_mail(  # pylint: disable-msg=too-many-positional-arguments
 
     icon = get_icon_from_severity(severity)
     msg = f"""\
-URL:    {task.url}
+URL:    {task.url} (IPv{task.ip_version})
 Check:  {task.check}
 Status: {severity}
 Time:   {result.submitted_at}
@@ -109,7 +158,9 @@ See results of task on {request.url_for('get_task_results_view', task_id=task.id
 """
 
     mail = EmailMessage()
-    mail["Subject"] = f"[Argos] {icon} {urlparse(task.url).netloc}: status {severity}"
+    mail[
+        "Subject"
+    ] = f"[Argos] {icon} {urlparse(task.url).netloc} (IPv{task.ip_version}): status {severity}"
     mail["From"] = config.mailfrom
     mail.set_content(msg)
 
@@ -152,9 +203,11 @@ def notify_with_gotify(  # pylint: disable-msg=too-many-positional-arguments
     elif severity == Severity.UNKNOWN:
         priority = 5
 
-    subject = f"{icon} {urlparse(task.url).netloc}: status {severity}"
+    subject = (
+        f"{icon} {urlparse(task.url).netloc} (IPv{task.ip_version}): status {severity}"
+    )
     msg = f"""\
-URL:    <{task.url}>\\
+URL:    <{task.url}> (IPv{task.ip_version})\\
 Check:  {task.check}\\
 Status: {severity}\\
 Time:   {result.submitted_at}\\
diff --git a/argos/server/migrations/versions/31255a412d63_add_form_data_to_tasks.py b/argos/server/migrations/versions/31255a412d63_add_form_data_to_tasks.py
new file mode 100644
index 0000000..bb4deaa
--- /dev/null
+++ b/argos/server/migrations/versions/31255a412d63_add_form_data_to_tasks.py
@@ -0,0 +1,28 @@
+"""Add request data to tasks
+
+Revision ID: 31255a412d63
+Revises: 80a29f64f91c
+Create Date: 2024-12-09 16:40:20.926138
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "31255a412d63"
+down_revision: Union[str, None] = "80a29f64f91c"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.add_column(sa.Column("request_data", sa.String(), nullable=True))
+
+
+def downgrade() -> None:
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.drop_column("request_data")
diff --git a/argos/server/migrations/versions/64f73a79b7d8_add_ip_version_to_checks.py b/argos/server/migrations/versions/64f73a79b7d8_add_ip_version_to_checks.py
new file mode 100644
index 0000000..0cd752a
--- /dev/null
+++ b/argos/server/migrations/versions/64f73a79b7d8_add_ip_version_to_checks.py
@@ -0,0 +1,34 @@
+"""Add IP version to checks
+
+Revision ID: 64f73a79b7d8
+Revises: a1e98cf72a5c
+Create Date: 2024-12-02 14:12:40.558033
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+from sqlalchemy.dialects.postgresql import ENUM
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "64f73a79b7d8"
+down_revision: Union[str, None] = "a1e98cf72a5c"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    enum = ENUM("4", "6", name="ip_version_enum", create_type=False)
+    enum.create(op.get_bind(), checkfirst=False)
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.add_column(
+            sa.Column("ip_version", enum, server_default="4", nullable=False)
+        )
+
+
+def downgrade() -> None:
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.drop_column("ip_version")
+        ENUM(name="ip_version_enum").drop(op.get_bind(), checkfirst=False)
diff --git a/argos/server/migrations/versions/80a29f64f91c_add_retries_before_notification_feature.py b/argos/server/migrations/versions/80a29f64f91c_add_retries_before_notification_feature.py
new file mode 100644
index 0000000..91ec086
--- /dev/null
+++ b/argos/server/migrations/versions/80a29f64f91c_add_retries_before_notification_feature.py
@@ -0,0 +1,41 @@
+"""Add retries before notification feature
+
+Revision ID: 80a29f64f91c
+Revises: 8b58ced14d6e
+Create Date: 2024-12-04 17:03:35.104368
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "80a29f64f91c"
+down_revision: Union[str, None] = "8b58ced14d6e"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.add_column(
+            sa.Column(
+                "retry_before_notification",
+                sa.Integer(),
+                server_default="0",
+                nullable=False,
+            )
+        )
+        batch_op.add_column(
+            sa.Column(
+                "contiguous_failures", sa.Integer(), server_default="0", nullable=False
+            )
+        )
+
+
+def downgrade() -> None:
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.drop_column("contiguous_failures")
+        batch_op.drop_column("retry_before_notification")
diff --git a/argos/server/migrations/versions/8b58ced14d6e_add_task_index.py b/argos/server/migrations/versions/8b58ced14d6e_add_task_index.py
new file mode 100644
index 0000000..8bbf313
--- /dev/null
+++ b/argos/server/migrations/versions/8b58ced14d6e_add_task_index.py
@@ -0,0 +1,35 @@
+"""Add task index
+
+Revision ID: 8b58ced14d6e
+Revises: 64f73a79b7d8
+Create Date: 2024-12-03 16:41:44.842213
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "8b58ced14d6e"
+down_revision: Union[str, None] = "64f73a79b7d8"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.add_column(sa.Column("task_group", sa.String(), nullable=True))
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.execute(
+            "UPDATE tasks SET task_group = method || '-' || ip_version || '-' || url"
+        )
+        batch_op.alter_column("task_group", nullable=False)
+        batch_op.create_index("similar_tasks", ["task_group"], unique=False)
+
+
+def downgrade() -> None:
+    with op.batch_alter_table("tasks", schema=None) as batch_op:
+        batch_op.drop_index("similar_tasks")
+        batch_op.drop_column("task_group")
diff --git a/argos/server/migrations/versions/bd4b4962696a_use_bigint_for_results_id_field.py b/argos/server/migrations/versions/bd4b4962696a_use_bigint_for_results_id_field.py
new file mode 100644
index 0000000..766428e
--- /dev/null
+++ b/argos/server/migrations/versions/bd4b4962696a_use_bigint_for_results_id_field.py
@@ -0,0 +1,44 @@
+"""Use bigint for results id field
+
+Revision ID: bd4b4962696a
+Revises: 31255a412d63
+Create Date: 2025-01-06 11:44:37.552965
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "bd4b4962696a"
+down_revision: Union[str, None] = "31255a412d63"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    if bind.engine.name != "sqlite":
+        with op.batch_alter_table("results", schema=None) as batch_op:
+            batch_op.alter_column(
+                "id",
+                existing_type=sa.INTEGER(),
+                type_=sa.BigInteger(),
+                existing_nullable=False,
+                autoincrement=True,
+            )
+
+
+def downgrade() -> None:
+    bind = op.get_bind()
+    if bind.engine.name != "sqlite":
+        with op.batch_alter_table("results", schema=None) as batch_op:
+            batch_op.alter_column(
+                "id",
+                existing_type=sa.BigInteger(),
+                type_=sa.INTEGER(),
+                existing_nullable=False,
+                autoincrement=True,
+            )
diff --git a/argos/server/models.py b/argos/server/models.py
index 33b05b9..c503e20 100644
--- a/argos/server/models.py
+++ b/argos/server/models.py
@@ -1,6 +1,7 @@
 """Database models"""
 
 from datetime import datetime, timedelta
+from hashlib import md5
 from typing import List, Literal
 
 from sqlalchemy import (
@@ -9,10 +10,23 @@ from sqlalchemy import (
     ForeignKey,
 )
 from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship
+from sqlalchemy.schema import Index
 
 from argos.checks import BaseCheck, get_registered_check
 from argos.schemas import WebsiteCheck
-from argos.schemas.utils import Method
+from argos.schemas.utils import IPVersion, Method
+
+
+def compute_task_group(context) -> str:
+    data = context.current_parameters["request_data"]
+    if data is None:
+        data = ""
+    return (
+        f"{context.current_parameters['method']}-"
+        f"{context.current_parameters['ip_version']}-"
+        f"{context.current_parameters['url']}-"
+        f"{md5(data.encode()).hexdigest()}"
+    )
 
 
 class Base(DeclarativeBase):
@@ -33,11 +47,16 @@ class Task(Base):
     # Info needed to run the task
     url: Mapped[str] = mapped_column()
     domain: Mapped[str] = mapped_column()
+    ip_version: Mapped[IPVersion] = mapped_column(
+        Enum("4", "6", name="ip_version_enum"),
+    )
     check: Mapped[str] = mapped_column()
     expected: Mapped[str] = mapped_column()
     frequency: Mapped[float] = mapped_column()
     recheck_delay: Mapped[float] = mapped_column(nullable=True)
     already_retried: Mapped[bool] = mapped_column(insert_default=False)
+    retry_before_notification: Mapped[int] = mapped_column(insert_default=0)
+    contiguous_failures: Mapped[int] = mapped_column(insert_default=0)
     method: Mapped[Method] = mapped_column(
         Enum(
             "GET",
@@ -53,12 +72,14 @@ class Task(Base):
         ),
         insert_default="GET",
     )
+    request_data: Mapped[str] = mapped_column(nullable=True)
 
     # Orchestration-related
     selected_by: Mapped[str] = mapped_column(nullable=True)
     selected_at: Mapped[datetime] = mapped_column(nullable=True)
     completed_at: Mapped[datetime] = mapped_column(nullable=True)
     next_run: Mapped[datetime] = mapped_column(nullable=True)
+    task_group: Mapped[str] = mapped_column(insert_default=compute_task_group)
 
     severity: Mapped[Literal["ok", "warning", "critical", "unknown"]] = mapped_column(
         Enum("ok", "warning", "critical", "unknown", name="severity"),
@@ -72,8 +93,8 @@ class Task(Base):
         passive_deletes=True,
     )
 
-    def __str__(self):
-        return f"DB Task {self.url} - {self.check} - {self.expected}"
+    def __str__(self) -> str:
+        return f"DB Task {self.url} (IPv{self.ip_version}) - {self.check} - {self.expected}"
 
     def get_check(self) -> BaseCheck:
         """Returns a check instance for this specific task"""
@@ -114,6 +135,9 @@ class Task(Base):
         return self.last_result.status
 
 
+Index("similar_tasks", Task.task_group)
+
+
 class Result(Base):
     """There are multiple results per task.
 
diff --git a/argos/server/queries.py b/argos/server/queries.py
index 94fc0f4..be9afd7 100644
--- a/argos/server/queries.py
+++ b/argos/server/queries.py
@@ -4,7 +4,7 @@ from hashlib import sha256
 from typing import List
 from urllib.parse import urljoin
 
-from sqlalchemy import asc, desc, func
+from sqlalchemy import asc, desc, func, Select
 from sqlalchemy.orm import Session
 
 from argos import schemas
@@ -14,15 +14,16 @@ from argos.server.models import Result, Task, ConfigCache, User
 
 async def list_tasks(db: Session, agent_id: str, limit: int = 100):
     """List tasks and mark them as selected"""
-    tasks = (
-        db.query(Task)
+    subquery = (
+        db.query(func.distinct(Task.task_group))
         .filter(
             Task.selected_by == None,  # noqa: E711
             ((Task.next_run <= datetime.now()) | (Task.next_run == None)),  # noqa: E711
         )
         .limit(limit)
-        .all()
+        .subquery()
     )
+    tasks = db.query(Task).filter(Task.task_group.in_(Select(subquery))).all()
 
     now = datetime.now()
     for task in tasks:
@@ -82,13 +83,22 @@ async def count_results(db: Session):
     return db.query(Result).count()
 
 
-async def has_config_changed(db: Session, config: schemas.Config) -> bool:
+async def has_config_changed(db: Session, config: schemas.Config) -> bool:  # pylint: disable-msg=too-many-statements
     """Check if websites config has changed by using a hashsum and a config cache"""
     websites_hash = sha256(str(config.websites).encode()).hexdigest()
     conf_caches = db.query(ConfigCache).all()
     same_config = True
+    keys = [
+        "websites_hash",
+        "general_frequency",
+        "general_recheck_delay",
+        "general_retry_before_notification",
+        "general_ipv4",
+        "general_ipv6",
+    ]
     if conf_caches:
         for conf in conf_caches:
+            keys.remove(conf.name)
             match conf.name:
                 case "websites_hash":
                     if conf.val != websites_hash:
@@ -105,9 +115,67 @@ async def has_config_changed(db: Session, config: schemas.Config) -> bool:
                         same_config = False
                         conf.val = str(config.general.recheck_delay)
                         conf.updated_at = datetime.now()
+                case "general_retry_before_notification":
+                    if conf.val != str(config.general.retry_before_notification):
+                        same_config = False
+                        conf.val = str(config.general.retry_before_notification)
+                        conf.updated_at = datetime.now()
+                case "general_ipv4":
+                    if conf.val != str(config.general.ipv4):
+                        same_config = False
+                        conf.val = str(config.general.ipv4)
+                        conf.updated_at = datetime.now()
+                case "general_ipv6":
+                    if conf.val != str(config.general.ipv6):
+                        same_config = False
+                        conf.val = str(config.general.ipv6)
+                        conf.updated_at = datetime.now()
+
+        for i in keys:
+            match i:
+                case "websites_hash":
+                    c = ConfigCache(
+                        name="websites_hash",
+                        val=websites_hash,
+                        updated_at=datetime.now(),
+                    )
+                case "general_frequency":
+                    c = ConfigCache(
+                        name="general_frequency",
+                        val=str(config.general.frequency),
+                        updated_at=datetime.now(),
+                    )
+                case "general_recheck_delay":
+                    c = ConfigCache(
+                        name="general_recheck_delay",
+                        val=str(config.general.recheck_delay),
+                        updated_at=datetime.now(),
+                    )
+                case "general_retry_before_notification":
+                    c = ConfigCache(
+                        name="general_retry_before_notification",
+                        val=str(config.general.retry_before_notification),
+                        updated_at=datetime.now(),
+                    )
+                case "general_ipv4":
+                    c = ConfigCache(
+                        name="general_ipv4",
+                        val=str(config.general.ipv4),
+                        updated_at=datetime.now(),
+                    )
+                case "general_ipv6":
+                    c = ConfigCache(
+                        name="general_ipv6",
+                        val=str(config.general.ipv6),
+                        updated_at=datetime.now(),
+                    )
+            db.add(c)
 
         db.commit()
 
+        if keys:
+            return True
+
         if same_config:
             return False
 
@@ -125,15 +193,33 @@ async def has_config_changed(db: Session, config: schemas.Config) -> bool:
             val=str(config.general.recheck_delay),
             updated_at=datetime.now(),
         )
+        gen_retry_before_notif = ConfigCache(
+            name="general_retry_before_notification",
+            val=str(config.general.retry_before_notification),
+            updated_at=datetime.now(),
+        )
+        gen_ipv4 = ConfigCache(
+            name="general_ipv4",
+            val=str(config.general.ipv4),
+            updated_at=datetime.now(),
+        )
+        gen_ipv6 = ConfigCache(
+            name="general_ipv6",
+            val=str(config.general.ipv6),
+            updated_at=datetime.now(),
+        )
         db.add(web_hash)
         db.add(gen_freq)
         db.add(gen_recheck)
+        db.add(gen_retry_before_notif)
+        db.add(gen_ipv4)
+        db.add(gen_ipv6)
         db.commit()
 
     return True
 
 
-async def update_from_config(db: Session, config: schemas.Config):
+async def update_from_config(db: Session, config: schemas.Config):  # pylint: disable-msg=too-many-branches
     """Update tasks from config file"""
     config_changed = await has_config_changed(db, config)
     if not config_changed:
@@ -145,61 +231,101 @@ async def update_from_config(db: Session, config: schemas.Config):
     tasks = []
     unique_properties = []
     seen_tasks: List[int] = []
-    for website in config.websites:
+    for website in config.websites:  # pylint: disable-msg=too-many-nested-blocks
         domain = str(website.domain)
         frequency = website.frequency or config.general.frequency
         recheck_delay = website.recheck_delay or config.general.recheck_delay
+        retry_before_notification = (
+            website.retry_before_notification
+            if website.retry_before_notification is not None
+            else config.general.retry_before_notification
+        )
+        ipv4 = website.ipv4 if website.ipv4 is not None else config.general.ipv4
+        ipv6 = website.ipv6 if website.ipv6 is not None else config.general.ipv6
+        if ipv4 is False and ipv6 is False:
+            logger.warning("IPv4 AND IPv6 are disabled on website %s!", domain)
+            continue
 
-        for p in website.paths:
-            url = urljoin(domain, str(p.path))
-            for check_key, expected in p.checks:
-                # Check the db for already existing tasks.
-                existing_tasks = (
-                    db.query(Task)
-                    .filter(
-                        Task.url == url,
-                        Task.method == p.method,
-                        Task.check == check_key,
-                        Task.expected == expected,
-                    )
-                    .all()
-                )
-                if existing_tasks:
-                    existing_task = existing_tasks[0]
-                    seen_tasks.append(existing_task.id)
-
-                    if frequency != existing_task.frequency:
-                        existing_task.frequency = frequency
-                    if recheck_delay != existing_task.recheck_delay:
-                        existing_task.recheck_delay = recheck_delay  # type: ignore[assignment]
-                    logger.debug(
-                        "Skipping db task creation for url=%s, "
-                        "method=%s, check_key=%s, expected=%s, "
-                        "frequency=%s, recheck_delay=%s.",
-                        url,
-                        p.method,
-                        check_key,
-                        expected,
-                        frequency,
-                        recheck_delay,
-                    )
-
-                else:
-                    properties = (url, check_key, expected)
-                    if properties not in unique_properties:
-                        unique_properties.append(properties)
-                        task = Task(
-                            domain=domain,
-                            url=url,
-                            method=p.method,
-                            check=check_key,
-                            expected=expected,
-                            frequency=frequency,
-                            recheck_delay=recheck_delay,
-                            already_retried=False,
+        for ip_version in ["4", "6"]:
+            for p in website.paths:
+                url = urljoin(domain, str(p.path))
+                for check_key, expected in p.checks:
+                    # Check the db for already existing tasks.
+                    existing_tasks = (
+                        db.query(Task)
+                        .filter(
+                            Task.url == url,
+                            Task.method == p.method,
+                            Task.request_data == p.request_data,
+                            Task.check == check_key,
+                            Task.expected == expected,
+                            Task.ip_version == ip_version,
                         )
-                        logger.debug("Adding a new task in the db: %s", task)
-                        tasks.append(task)
+                        .all()
+                    )
+
+                    if (ip_version == "4" and ipv4 is False) or (
+                        ip_version == "6" and ipv6 is False
+                    ):
+                        continue
+
+                    if existing_tasks:
+                        existing_task = existing_tasks[0]
+
+                        seen_tasks.append(existing_task.id)
+
+                        if frequency != existing_task.frequency:
+                            existing_task.frequency = frequency
+                        if recheck_delay != existing_task.recheck_delay:
+                            existing_task.recheck_delay = recheck_delay  # type: ignore[assignment]
+                        if (
+                            retry_before_notification
+                            != existing_task.retry_before_notification
+                        ):
+                            existing_task.retry_before_notification = (
+                                retry_before_notification
+                            )
+                        logger.debug(
+                            "Skipping db task creation for url=%s, "
+                            "method=%s, check_key=%s, expected=%s, "
+                            "frequency=%s, recheck_delay=%s, "
+                            "retry_before_notification=%s, ip_version=%s.",
+                            url,
+                            p.method,
+                            check_key,
+                            expected,
+                            frequency,
+                            recheck_delay,
+                            retry_before_notification,
+                            ip_version,
+                        )
+
+                    else:
+                        properties = (
+                            url,
+                            p.method,
+                            check_key,
+                            expected,
+                            ip_version,
+                            p.request_data,
+                        )
+                        if properties not in unique_properties:
+                            unique_properties.append(properties)
+                            task = Task(
+                                domain=domain,
+                                url=url,
+                                ip_version=ip_version,
+                                method=p.method,
+                                request_data=p.request_data,
+                                check=check_key,
+                                expected=expected,
+                                frequency=frequency,
+                                recheck_delay=recheck_delay,
+                                retry_before_notification=retry_before_notification,
+                                already_retried=False,
+                            )
+                            logger.debug("Adding a new task in the db: %s", task)
+                            tasks.append(task)
 
     db.add_all(tasks)
     db.commit()
diff --git a/argos/server/routes/api.py b/argos/server/routes/api.py
index cc96132..78dd83d 100644
--- a/argos/server/routes/api.py
+++ b/argos/server/routes/api.py
@@ -7,7 +7,7 @@ from sqlalchemy.orm import Session
 from argos.logging import logger
 from argos.schemas import AgentResult, Config, Task
 from argos.server import queries
-from argos.server.alerting import handle_alert
+from argos.server.alerting import handle_alert, need_alert
 from argos.server.routes.dependencies import get_config, get_db, verify_token
 
 route = APIRouter()
@@ -58,16 +58,26 @@ async def create_results(  # pylint: disable-msg=too-many-positional-arguments
             logger.error("Unable to find task %i", agent_result.task_id)
         else:
             last_severity = task.severity
+            last_severity_update = task.last_severity_update
             result = await queries.create_result(db, agent_result, agent_id)
             check = task.get_check()
             status, severity = await check.finalize(config, result, **result.context)
             result.set_status(status, severity)
             task.set_times_severity_and_deselect(severity, result.submitted_at)
 
-            # Don’t create an alert if the severity has not changed
-            if last_severity != severity:
+            send_notif = need_alert(
+                last_severity, last_severity_update, severity, status, task
+            )
+
+            if send_notif:
                 background_tasks.add_task(
-                    handle_alert, config, result, task, severity, last_severity, request
+                    handle_alert,
+                    config,
+                    result,
+                    task,
+                    severity,
+                    last_severity,
+                    request,
                 )
 
             db_results.append(result)
diff --git a/argos/server/routes/views.py b/argos/server/routes/views.py
index ae2f51c..3242972 100644
--- a/argos/server/routes/views.py
+++ b/argos/server/routes/views.py
@@ -357,8 +357,21 @@ async def set_refresh_cookies_view(
         request.url_for("get_severity_counts_view"),
         status_code=status.HTTP_303_SEE_OTHER,
     )
-    response.set_cookie(key="auto_refresh_enabled", value=str(auto_refresh_enabled))
+    # Cookies’ age in Chrome can’t be more than 400 days
+    # https://developer.chrome.com/blog/cookie-max-age-expires
+    delta = int(timedelta(days=400).total_seconds())
     response.set_cookie(
-        key="auto_refresh_seconds", value=str(max(5, int(auto_refresh_seconds)))
+        key="auto_refresh_enabled",
+        value=str(auto_refresh_enabled),
+        httponly=True,
+        samesite="strict",
+        expires=delta,
+    )
+    response.set_cookie(
+        key="auto_refresh_seconds",
+        value=str(max(5, int(auto_refresh_seconds))),
+        httponly=True,
+        samesite="strict",
+        expires=delta,
     )
     return response
diff --git a/argos/server/templates/domain.html b/argos/server/templates/domain.html
index fae614f..57d0700 100644
--- a/argos/server/templates/domain.html
+++ b/argos/server/templates/domain.html
@@ -16,7 +16,7 @@
         <tbody id="domains-body">
             {% for task in tasks %}
             <tr scope="row">
-                <td>{{ task.url }}</td>
+                <td>{{ task.url }} (IPv{{ task.ip_version }})</td>
                 <td>{{ task.check }}</td>
                 <td class="status highlight">
                     {% if task.status %}
diff --git a/tests/config.yaml b/tests/config.yaml
index 82f055b..a1cec52 100644
--- a/tests/config.yaml
+++ b/tests/config.yaml
@@ -1,6 +1,8 @@
+---
 general:
   db:
-    # The database URL, as defined in SQLAlchemy docs : https://docs.sqlalchemy.org/en/20/core/engines.html#database-urls
+    # The database URL, as defined in SQLAlchemy docs:
+    # https://docs.sqlalchemy.org/en/20/core/engines.html#database-urls
     url: "sqlite:////tmp/test-argos.db"
   env: test
   cookie_secret: "foo-bar-baz"
diff --git a/tests/test_api.py b/tests/test_api.py
index 9c9ab5d..b85716a 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -21,7 +21,7 @@ def test_tasks_retrieval_and_results(authorized_client, app):
         assert response.status_code == 200
 
         tasks = response.json()
-        assert len(tasks) == 2
+        assert len(tasks) == 4
 
         results = []
         for task in tasks:
@@ -33,7 +33,7 @@ def test_tasks_retrieval_and_results(authorized_client, app):
         response = client.post("/api/results", json=data)
 
         assert response.status_code == 201
-        assert app.state.db.query(models.Result).count() == 2
+        assert app.state.db.query(models.Result).count() == 4
 
         # The list of tasks should be empty now
         response = client.get("/api/tasks")
@@ -60,6 +60,7 @@ def ssl_task(db):
     task = models.Task(
         url="https://exemple.com/",
         domain="https://exemple.com/",
+        ip_version="6",
         method="GET",
         check="ssl-certificate-expiration",
         expected="on-check",
diff --git a/tests/test_checks.py b/tests/test_checks.py
index 28fe2fc..c3a458d 100644
--- a/tests/test_checks.py
+++ b/tests/test_checks.py
@@ -35,8 +35,13 @@ def ssl_task(now):
         id=1,
         url="https://example.org",
         domain="https://example.org",
+        ip_version="6",
         method="GET",
+        request_data=None,
+        task_group="GET-6-https://example.org",
         check="ssl-certificate-expiration",
+        retry_before_notification=0,
+        contiguous_failures=0,
         expected="on-check",
         selected_at=now,
         selected_by="pytest",
diff --git a/tests/test_queries.py b/tests/test_queries.py
index c468362..452dfe9 100644
--- a/tests/test_queries.py
+++ b/tests/test_queries.py
@@ -70,7 +70,7 @@ async def test_update_from_config_with_duplicate_tasks(db, empty_config):  #  py
     await queries.update_from_config(db, empty_config)
 
     # Only one path has been saved in the database
-    assert db.query(Task).count() == 1
+    assert db.query(Task).count() == 2
 
     # Calling again with the same data works, and will not result in more tasks being
     # created.
@@ -87,6 +87,7 @@ async def test_update_from_config_db_can_remove_duplicates_and_old_tasks(
     same_task = Task(
         url=task.url,
         domain=task.domain,
+        ip_version="6",
         check=task.check,
         expected=task.expected,
         frequency=task.frequency,
@@ -108,7 +109,7 @@ async def test_update_from_config_db_can_remove_duplicates_and_old_tasks(
     empty_config.websites = [website]
 
     await queries.update_from_config(db, empty_config)
-    assert db.query(Task).count() == 2
+    assert db.query(Task).count() == 4
 
     website = schemas.config.Website(
         domain=task.domain,
@@ -122,7 +123,7 @@ async def test_update_from_config_db_can_remove_duplicates_and_old_tasks(
     empty_config.websites = [website]
 
     await queries.update_from_config(db, empty_config)
-    assert db.query(Task).count() == 1
+    assert db.query(Task).count() == 2
 
 
 @pytest.mark.asyncio
@@ -136,7 +137,7 @@ async def test_update_from_config_db_updates_existing_tasks(db, empty_config, ta
     empty_config.websites = [website]
 
     await queries.update_from_config(db, empty_config)
-    assert db.query(Task).count() == 1
+    assert db.query(Task).count() == 2
 
 
 @pytest.mark.asyncio
@@ -212,6 +213,7 @@ def task(db):
     _task = Task(
         url="https://www.example.com",
         domain="https://www.example.com",
+        ip_version="6",
         check="body-contains",
         expected="foo",
         frequency=1,
@@ -271,6 +273,7 @@ def ten_locked_tasks(db):
         _task = Task(
             url="https://www.example.com",
             domain="example.com",
+            ip_version="6",
             check="body-contains",
             expected="foo",
             frequency=1,
@@ -291,6 +294,7 @@ def ten_tasks(db):
         _task = Task(
             url="https://www.example.com",
             domain="example.com",
+            ip_version="6",
             check="body-contains",
             expected="foo",
             frequency=1,
@@ -311,6 +315,7 @@ def ten_warning_tasks(db):
         _task = Task(
             url="https://www.example.com",
             domain="example.com",
+            ip_version="6",
             check="body-contains",
             expected="foo",
             frequency=1,
@@ -331,6 +336,7 @@ def ten_critical_tasks(db):
         _task = Task(
             url="https://www.example.com",
             domain="example.com",
+            ip_version="6",
             check="body-contains",
             expected="foo",
             frequency=1,
@@ -351,6 +357,7 @@ def ten_ok_tasks(db):
         _task = Task(
             url="https://www.example.com",
             domain="example.com",
+            ip_version="6",
             check="body-contains",
             expected="foo",
             frequency=1,
diff --git a/tests/websites.yaml b/tests/websites.yaml
index f2d50dc..da19ae9 100644
--- a/tests/websites.yaml
+++ b/tests/websites.yaml
@@ -1,6 +1,7 @@
+---
 - domain: "https://mypads.framapad.org"
   paths:
     - path: "/mypads/"
       checks:
         - status-is: 200
-        - body-contains: '<div id= "mypads"></div>'
\ No newline at end of file
+        - body-contains: '<div id= "mypads"></div>'