# Why is Exim installed, firewall configuration, how to change the turn port?

**URL:** <https://forum.delta.chat/t/why-is-exim-installed-firewall-configuration-how-to-change-the-turn-port/4465>\
**Category:** Mutual Help\
**Tags:** server-config, chatmail\
**Created:** [December 13, 2025, 8:07pm UTC](https://forum.delta.chat/t/why-is-exim-installed-firewall-configuration-how-to-change-the-turn-port/4465 "2025-12-13T20:07:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![bestman](https://forum.delta.chat/letter_avatar_proxy/v4/letter/b/96bed5/32.png) [@bestman](https://forum.delta.chat/u/bestman)\
**Post date:** [December 13, 2025, 8:07pm UTC](https://forum.delta.chat/t/why-is-exim-installed-firewall-configuration-how-to-change-the-turn-port/4465/1 "2025-12-13T20:07:42Z")

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Hi all, thanks for your help, read the [documentation](https://chatmail.at/doc/relay/overview.html) and have a couple of questions:

1. As I can see, Exim is also installed on the Debian server, although I don’t see it in the running ones, why is it installed?

```auto
ls /etc/exim4/
conf.d exim4.conf.template passwd.client update-exim4.conf.conf

```

1. Setting up a firewall as I see from the documentation and ports that are now open, I think it looks like this(please correct if I’m missing something)

```auto
# SSH
ufw allow 22/tcp comment 'ssh'
# Nginx HTTP/HTTPS
ufw allow 80/tcp comment 'nginx http'
ufw allow 443/tcp comment 'nginx https'
# turn UDP
ufw allow 3478/udp comment 'coturn udp'
# turn 
ufw allow 49152:65535/ comment `udp call`
# Mail
ufw allow 587/tcp comment 'mail'
ufw allow 465/tcp comment 'mail'
ufw allow 993/tcp comment 'mail'
ufw allow 25/tcp comment 'mail'
ufw allow 143/tcp comment `open it??'
ufw enable

```

1. Can I change the server’s turn port to 5478, for example?
2. Did not find where the [turn server is installed](https://github.com/chatmail/chatmail-turn?tab=readme-ov-file), as well as its configuration file?

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<div class="post-metadata">

**Author:** ![WofWca](https://forum.delta.chat/user_avatar/forum.delta.chat/wofwca/32/1702_2.png) [@WofWca](https://forum.delta.chat/u/WofWca)\
**Post date:** [December 14, 2025, 7:04am UTC](https://forum.delta.chat/t/why-is-exim-installed-firewall-configuration-how-to-change-the-turn-port/4465/2 "2025-12-14T07:04:12Z")

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> [@bestman](#):
>
> Can I change the server’s turn port to 5478, for example?

No, currently it’s hard-coded, but I don’t recall a particular reason for that having to be the case, except maybe [this](https://github.com/chatmail/core/pull/7218#discussion_r2383950827).

> <https://github.com/chatmail/relay/blob/c84ddf69e8e7a37d5a204fc284c736f1587662be/chatmaild/src/chatmaild/metadata.py#L103-L106>

> <https://github.com/chatmail/chatmail-turn/blob/7f7cc0c0f24108dee6acc62e00694512bd3fe399/src/main.rs#L88-L90>

* * *

> [@bestman](#):
>
> Did not find where the [turn server is installed](https://github.com/chatmail/chatmail-turn?tab=readme-ov-file), as well as its configuration file?

It’s installed to `/usr/local/bin/chatmail-turn`:

> <https://github.com/chatmail/relay/blob/c84ddf69e8e7a37d5a204fc284c736f1587662be/cmdeploy/src/cmdeploy/deployers.py#L319-L322>

And then launched from here:

> <https://github.com/chatmail/relay/blob/c84ddf69e8e7a37d5a204fc284c736f1587662be/cmdeploy/src/cmdeploy/service/turnserver.service.f#L8>

There is nothing to configure currently

> <https://github.com/chatmail/chatmail-turn/blob/7f7cc0c0f24108dee6acc62e00694512bd3fe399/src/main.rs#L66-L79>

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<div class="post-metadata">

**Author:** ![r10s](https://forum.delta.chat/user_avatar/forum.delta.chat/r10s/32/1513_2.png) [@r10s](https://forum.delta.chat/u/r10s)\
**Post date:** [October 6, 2026, 3:28pm UTC](https://forum.delta.chat/t/why-is-exim-installed-firewall-configuration-how-to-change-the-turn-port/4465/3 "2026-10-06T15:28:58Z")

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