mailcow-dockerized-docs/docs/post_installation/firststeps-ip_bindings.en.md

!!! warning Changing the binding does not affect source NAT. See SNAT for required steps.

IPv4 binding

To adjust one or multiple IPv4 bindings, open mailcow.conf and edit one, multiple or all variables as per your needs:

# For technical reasons, http bindings are a bit different from other service bindings.
# You will find the following variables, separated by a bind address and its port:
# Example: HTTP_BIND=1.2.3.4

HTTP_PORT=80
HTTP_BIND=
HTTPS_PORT=443
HTTPS_BIND=

# Other services are bound by using the following format:
# SMTP_PORT=1.2.3.4:25 will bind SMTP to the IP 1.2.3.4 on port 25
# Important! Specifying an IPv4 address will skip all IPv6 bindings since Docker 20.x.
# doveadm, SQL as well as Solr are bound to local ports only, please do not change that, unless you know what you are doing.

SMTP_PORT=25
SMTPS_PORT=465
SUBMISSION_PORT=587
IMAP_PORT=143
IMAPS_PORT=993
POP_PORT=110
POPS_PORT=995
SIEVE_PORT=4190
DOVEADM_PORT=127.0.0.1:19991
SQL_PORT=127.0.0.1:13306
SOLR_PORT=127.0.0.1:18983

To apply your changes, run docker compose down followed by docker compose up -d.

IPv6 binding

Changing IPv6 bindings is different from IPv4. Again, this has a technical background.

A docker compose.override.yml file will be used instead of editing the docker compose.yml file directly. This is to maintain updatability, as the docker compose.yml file gets updated regularly and your changes will most likely be overwritten.

Edit to create a file docker compose.override.yml with the following content. Its content will be merged with the productive docker compose.yml file.

An imaginary IPv6 2a00:dead:beef::abc is given. The first suffix :PORT1 defines the external port, while the second suffix :PORT2 routes to the corresponding port inside the container and must not be changed.

version: '2.1'
services:

    dovecot-mailcow:
      ports:
        - '2a00:dead:beef::abc:143:143'
        - '2a00:dead:beef::abc:993:993'
        - '2a00:dead:beef::abc:110:110'
        - '2a00:dead:beef::abc:995:995'
        - '2a00:dead:beef::abc:4190:4190'

    postfix-mailcow:
      ports:
        - '2a00:dead:beef::abc:25:25'
        - '2a00:dead:beef::abc:465:465'
        - '2a00:dead:beef::abc:587:587'

    nginx-mailcow:
      ports:
        - '2a00:dead:beef::abc:80:80'
        - '2a00:dead:beef::abc:443:443'

To apply your changes, run docker compose down followed by docker compose up -d.