Mailcow logs viewer: A faster, cool way to monitor your emails

shlomi

Hi everyone,

While mailcow is an amazing suite, I often found the built-in log viewing options a bit clunky when I needed to debug something quickly (its even worse from a mobile device). Searching through Rspamd or Postfix logs in Mailcow GUI isn’t always the smoothest experience.

To make my life (and hopefully yours) easier, I created mailcow-logs-viewer.

GitHub

Why I built this:
The main goal was to have a simple, responsive interface where I can check why an email is stuck or why an IP was blocked, without needing to open a terminal or navigate through the full Admin UI.

Instant Filtering: A clean search bar that actually feels fast. Filter by container or keyword (Postfix, Dovecot, Rspamd, etc.) instantly.

Minimalist & Lightweight: It doesn’t try to replace the mailcow UI; it just does one thing - viewing logs - extremely well and quickly.

Real-time Streaming: Uses Socket.io to push logs to your browser the moment they happen.

How it looks:
Main
Messages

Quick Setup:
It runs as a lightweight container. Full instructions are in the repo.

I’d love to hear what your opinion 😎

Gebemsea

Thanks @shlomi. Like it! Great instructions, thanks. Got it installed and running over breakfast 🙂) FYI: Home lab running XCP-NG 8.3 hypervisors; Mailcow Logs viewer on Ubuntu LTS VM, separate to MC (of course).

This is something I’ve wanted in running Mailcow for the last 8 years- that is, to separate IT logs from Management data from Security data - and easy to use as well. I think this will do it for me.

Setup instructions were brilliant - hardest thing was to find the “API” expansion button in Mailcow! It’s too discreet… something for the mailcow team perhaps.

The one initial ‘nice to have’ might be to categorise emails as internal | inbound | outbound instead of just inbound | outbound.

shlomi

Gebemsea
Glad to hear you liked it.
I didn’t even think about internal emails, I’ll definitely check that out.
From a quick test on a server with one domain it’s pretty easy to add, but on a server with multiple domains it’ll be a bit more complicated.
I’ll have to check the logs and try to see if it’s something that can be done.

shlomi

Gebemsea
In the next release

smart

Hi @shlomi,

just read you post
installed it right away with no issue.

What a masterpiece!
Like it very very much
Even the Design ist mailcow’ish

BIG THANK YOU !

FYI: using it with 2 domains (but running <1h, so not much to complain 😉 )

Cisco30

Hi
2026 is off to a great start thanks to you! Superb work, I’m very impressed by the quality, the installation is very clear, I adopted it immediately, thank you so much!

maybl8

Cisco30
For the ip address is it the local or the public that is needed for the api key

Cisco30

maybl8

DocFraggle

maybl8 As I run this in parallel to mailcow on the same server, i just put my docker network (even more than that 😃 ) in there

172.16.0.0/12

It’s safer than disabling the IP check 😉

@shlomi I love this!! It would be a great addition if one could customize the date/time format to one’s liking

maybl8

DocFraggle
I always do something wrong when I start messing with the system.
Since configuring this I am getting these errors:

ostfix-mailcow-1  | Jan  5 08:31:55 5744f5843a86 postfix/smtp[386]: warning: host mail.dccathome.com[75.115.164.173]:25 greeted me with my own hostname mail.dccathome.com
postfix-mailcow-1  | Jan  5 08:31:55 5744f5843a86 postfix/smtp[386]: warning: host mail.dccathome.com[75.115.164.173]:25 replied to HELO/EHLO with my own hostname mail.dccathome.com
postfix-mailcow-1  | Jan  5 08:31:55 5744f5843a86 postfix/smtp[386]: DE6A5205139: to=<postmaster@mail.dccathome.com>, orig_to=<postmaster>, relay=mail.dccathome.com[75.115.164.173]:25, delay=3.2, delays=0.04/0.06/3.1/0, dsn=5.4.6, status=bounced (mail for mail.dccathome.com loops back to myself)
postfix-mailcow-1  | Jan  5 08:31:55 5744f5843a86 postfix/postscreen[387]: DISCONNECT [75.115.164.173]:41014
postfix-mailcow-1  | Jan  5 08:31:55 5744f5843a86 postfix/bounce[400]: warning: DE6A5205139: undeliverable postmaster notification discarded
postfix-mailcow-1  | Jan  5 08:32:47 5744f5843a86 postfix/postscreen[387]: CONNECT from [75.115.164.173]:48750 to [172.22.1.253]:25
postfix-mailcow-1  | Jan  5 08:32:47 5744f5843a86 whitelist_forwardinghosts: Look up 75.115.164.173 on whitelist, result 200 DUNNO
postfix-mailcow-1  | Jan  5 08:32:47 5744f5843a86 postfix/dnsblog[398]: addr 75.115.164.173 listed by domain zen.spamhaus.org as 127.0.0.10
postfix-mailcow-1  | Jan  5 08:32:50 5744f5843a86 postfix/postscreen[387]: DNSBL rank 8 for [75.115.164.173]:48750
postfix-mailcow-1  | Jan  5 08:32:50 5744f5843a86 postfix/smtp[386]: warning: host mail.dccathome.com[75.115.164.173]:25 greeted me with my own hostname mail.dccathome.com
postfix-mailcow-1  | Jan  5 08:32:50 5744f5843a86 postfix/smtp[386]: warning: host mail.dccathome.com[75.115.164.173]:25 replied to HELO/EHLO with my own hostname mail.dccathome.com
postfix-mailcow-1  | Jan  5 08:32:50 5744f5843a86 postfix/smtp[386]: 2B4E4200026: to=<postmaster@mail.dccathome.com>, orig_to=<postmaster>, relay=mail.dccathome.com[75.115.164.173]:25, delay=3, delays=0.07/0.02/2.9/0, dsn=5.4.6, status=bounced (mail for mail.dccathome.com loops back to myself)
postfix-mailcow-1  | Jan  5 08:32:50 5744f5843a86 postfix/bounce[400]: warning: 2B4E4200026: undeliverable postmaster notification discarded
postfix-mailcow-1  | Jan  5 08:32:50 5744f5843a86 postfix/postscreen[387]: DISCONNECT [75.115.164.173]:48750

also I am not getting any logs at the :8080 page

maybl8

DocFraggle
Is this the ip address i should be using for my server:
imap-login: Disconnected: Aborted login by logging out (no auth attempts in 0 secs): user=<>, rip=172.22.1.7, lip=172.22.1.250

shlomi

DocFraggle
Thanks.
The date and time was a pain to fix.
What do you mean by customize?

Cisco30

DocFraggle
Hi
That’s true, but in my cluster, all traffic is distributed by HAProxy, even when allowing all IPs on the API. To get Mailcow logs viewer working, port 443 is mandatory… otherwise, there’s no response.
But just like you, I find Shlomi’s work on reading the logs impressive.

DocFraggle

maybl8 when I start messing with the system

What did you do except for setting the API IP? And check why your system is listed at Spamhaus…

maybl8

DocFraggle
I added the line from the instructions in postfix extra.cf.
I undid the API use and removed the postfix line and rebooted the server and mail is working again.
First time I have seen the spamhaus error. I will look into this.
Can’t get a test email from spamhaus

postfix-mailcow-1  | Jan  5 09:14:52 5744f5843a86 postfix/cleanup[560]: F1D862001AF: prepend: header Content-Transfer-Encoding: 7bit from unlisted.blt.spamhaus.net[199.168.89.101]; from=<auth@unlisted.blt.spamhaus.net> to=<danc@dccathome.com> proto=ESMTP helo=<unlisted.blt.spamhaus.net>: List-Unsubscribe: mailto:<contact@mydomain.com>?subject=unsubscribe>"
postfix-mailcow-1  | Jan  5 09:14:52 5744f5843a86 postfix/cleanup[560]: F1D862001AF: milter-reject: END-OF-MESSAGE from unlisted.blt.spamhaus.net[199.168.89.101]: 4.7.1 Greylisted, please try again later; from=<auth@unlisted.blt.spamhaus.net> to=<danc@dccathome.com> proto=ESMTP helo=<unlisted.blt.spamhaus.net>
postfix-mailcow-1  | Jan  5 09:14:52 5744f5843a86 postfix/smtpd[559]: disconnect from unlisted.blt.spamhaus.net[199.168.89.101] ehlo=1 mail=1 rcpt=1 data=0/1 quit=1 commands=4/5

finally got it

DocFraggle

maybl8 ah ok, I didn’t add the line at all, didn’t see this 😅

shlomi

DocFraggle
If you don’t send email via smtp then is not an issue.
From what I’ve seen, some SMTPs don’t create a message ID, so it’s impossible to match the logs between rspamd and postfix.

[unknown]
Thank you for the explanation. I’ll check it out

DocFraggle

maybl8 No, you have to look at the logs of your php-fpm container

maybl8

DocFraggle
so my logs are showing this:

php-fpm-mailcow-1  | 172.22.1.10 -  05/Jan/2026:10:45:21 -0500 "GET /admin/system.php" 200
php-fpm-mailcow-1  | 172.22.1.10 -  05/Jan/2026:10:45:22 -0500 "GET /index.php" 200
php-fpm-mailcow-1  | 172.22.1.10 -  05/Jan/2026:10:45:22 -0500 "GET /json_api.php" 200
php-fpm-mailcow-1  | 172.22.1.10 -  05/Jan/2026:10:45:22 -0500 "GET /json_api.php" 200
php-fpm-mailcow-1  | 172.22.1.10 -  05/Jan/2026:10:45:23 -0500 "GET /json_api.php" 200
php-fpm-mailcow-1  | 172.22.1.10 -  05/Jan/2026:10:45:23 -0500 "GET /json_api.php" 200
php-fpm-mailcow-1  | 172.22.1.10 -  05/Jan/2026:10:45:30 -0500 "HEAD /forwardinghosts.php" 200

And I put this in the API ip address:
172.22.0.0/12

I put the .env file and the docker-compose.yml in a subfolder of mailcow-dockeized . Is that correct.

DocFraggle

maybl8 I suggest you add 172.16.0.0/12, but yes, that’s correct if your mailcow-logs instance is running on the same docket host

maybl8

maybl8 I put the .env file and the docker-compose.yml in a subfolder of mailcow-dockeized . Is that correct.

This is what I did.
Never got he 8080 page to show anything and checking all the logs. Nothing ever showed it was working.
It just kept messing up my mail from receiving mail with the errors I listed in my posts.

the only file I edited that existed was the postfix extra.conf

maybl8

DocFraggle
Now I can’t receive any emails. I don’t know why getting this message:
I’m about to abandon this whole log thing.

postfix-mailcow-1  | Jan  5 12:20:25 5744f5843a86 postfix/smtpd[458]: NOQUEUE: milter-reject: MAIL from mout.gmx.net[212.227.17.20]: 451 4.7.1 Service unavailable - try again later; from=<dcihon@gmx.com> proto=ESMTP helo=<mout.gmx.net>
postfix-mailcow-1  | Jan  5 12:20:40 5744f5843a86 postfix/smtpd[457]: lost connection after QUIT from mout.gmx.net[212.227.15.19]
postfix-mailcow-1  | Jan  5 12:20:40 5744f5843a86 postfix/smtpd[457]: disconnect from mout.gmx.net[212.227.15.19] ehlo=2 starttls=0/1 mail=0/1 rcpt=0/1 data=0/1 quit=0/1 commands=2/7
postfix-mailcow-1  | Jan  5 12:20:46 5744f5843a86 postfix/smtpd[458]: lost connection after QUIT from mout.gmx.net[212.227.17.20]
postfix-mailcow-1  | Jan  5 12:20:46 5744f5843a86 postfix/smtpd[458]: disconnect from mout.gmx.net[212.227.17.20] ehlo=2 starttls=0/1 mail=0/1 rcpt=0/1 data=0/1 quit=0/1 commands=2/7

This is weird
Ran
sudo docker compose up -d
It recreated dovecot container
Container mailcowdockerized-dovecot-mailcow-1 Recreated
and its working again.
I quit with this log thing.

DocFraggle

shlomi My browser shows the time with AM/PM and the date in US format, it would be nice to customize it to your country’s format like 24h etc ☺️

DocFraggle

shlomi Sorry, I just realized it’s my OS setting in my Windows VM, it’s the German format on my mobile’s Chrome browser 😅