So a few days ago, the Q’s Place web server ran out of space; this was related to Kopia backup caching as it couldn’t reach the remote storage server but that’s for another day!

Unfortunately because of this, when I cleared the Kopia cache up and freed the required space up my mail server failed.

lipwig.qsplace.co.uk postfix/proxymap[424440]: panic: dict_db_sequence: no cursor
lipwig.qsplace.co.uk postfix/tlsmgr[423289]: warning: dict_proxy_sequence: service private/proxywrite socket: Success
lipwig.qsplace.co.uk postfix/postscreen[424323]: warning: dict_proxy_lookup: service private/proxywrite socket: Connection reset by peer
lipwig.qsplace.co.uk postfix/master[423255]: warning: process /usr/libexec/postfix/proxymap pid 424440 killed by signal 6
lipwig.qsplace.co.uk postfix/master[423255]: warning: /usr/libexec/postfix/proxymap: bad command startup -- throttling

This is one that I’ve not come across before, and took a little head scratching.

My first fix is to always to run “upcp -b”

ApisCP is build on Ansible and it does a bloody good job at fixing it’s self; unfortunately not this time?!?

Next was to look at the error which lead me to 1 year old posts about postfix bugs, this wasn’t the issue.

So I moved onto the “switch it off and back on method” still nothing; so step 2 reinstall postfix and related packages

[root@lipwig yum.repos.d]# yum provides /usr/libexec/postfix/proxymap
Last metadata expiration check: 0:05:16 ago on Mon Aug 15 18:50:25 2022.
postfix-2:3.5.8-4.el8.x86_64 : Postfix Mail Transport Agent
Repo : baseos
Matched from:
Filename : /usr/libexec/postfix/proxymap

postfix-3:3.3.7-1.apnscp.x86_64 : Postfix Mail Transport Agent
Repo : apnscp
Matched from:
Filename : /usr/libexec/postfix/proxymap

postfix-3:3.3.12-1.apnscp.x86_64 : Postfix Mail Transport Agent
Repo : apnscp
Matched from:
Filename : /usr/libexec/postfix/proxymap

postfix-3:3.5.6-1.apnscp.x86_64 : Postfix Mail Transport Agent
Repo : apnscp-updates
Matched from:
Filename : /usr/libexec/postfix/proxymap

postfix-3:3.5.9-1.apnscp.x86_64 : Postfix Mail Transport Agent
Repo : apnscp-updates
Matched from:
Filename : /usr/libexec/postfix/proxymap

postfix-3:3.5.15-1.apnscp.x86_64 : Postfix Mail Transport Agent
Repo : @System
Matched from:
Filename : /usr/libexec/postfix/proxymap

postfix-3:3.5.15-1.apnscp.x86_64 : Postfix Mail Transport Agent
Repo : apnscp-updates
Matched from:
Filename : /usr/libexec/postfix/proxymap

Super! I thought, wrong! When I tried to send an email again it failed; however this time showed a different error

Aug 15 21:11:28 lipwig.qsplace.co.uk postfix/proxymap[427599]: fatal: error [-30986] seeking /var/lib/postfix/smtpd_scache.db: Success

Well that looks, sounds, smells and tastes like a cache file; so lets treat it as such

[root@lipwig log]# systemctl stop postfix.service
[root@lipwig log]# rm -f /var/lib/postfix/smtpd_scache.db
[root@lipwig log]# systemctl start postfix.service
[root@lipwig log]# systemctl status postfix.service

[root@lipwig log]# systemctl status postfix.service
● postfix.service - Postfix Mail Transport Agent
Loaded: loaded (/usr/lib/systemd/system/postfix.service; enabled; vendor preset: disabled)
Active: active (running) since Mon 2022-08-15 21:13:03 BST; 5s ago
Process: 427632 ExecStop=/usr/sbin/postfix stop (code=exited, status=0/SUCCESS)
Process: 427652 ExecStart=/usr/sbin/postfix start (code=exited, status=0/SUCCESS)
Process: 427651 ExecStartPre=/usr/libexec/postfix/chroot-update (code=exited, status=0/SUCCESS)
Process: 427648 ExecStartPre=/usr/libexec/postfix/aliasesdb (code=exited, status=0/SUCCESS)
Main PID: 427728 (master)
Tasks: 12 (limit: 24288)
Memory: 26.4M
CGroup: /system.slice/postfix.service
├─427728 /usr/libexec/postfix/master -w
├─427729 pickup -l -t unix -u
├─427730 qmgr -l -t unix -u
├─427731 postscreen -l -n 250 -t inet -u -s 2 -o smtpd_sasl_auth_enable=yes
├─427732 proxymap -l -n proxywrite -t unix -u
├─427733 smtpd -t pass -u -o stress= -o smtpd_sasl_auth_enable=yes -o smtpd_upstream_proxy_protocol=
├─427734 proxymap -t unix -u
├─427735 tlsmgr -l -t unix -u
├─427751 trivial-rewrite -n rewrite -t unix -u
├─427755 cleanup -z -t unix -u
├─427759 local -t unix
└─427761 pipe -n localmaildrop -t unix flags=XODRhu user=mail argv=/usr/bin/maildrop -d ${user} ${extension} ${recipient} ${user} ${nexthop}

Aug 15 21:13:03 lipwig.qsplace.co.uk systemd[1]: Started Postfix Mail Transport Agent.
Aug 15 21:13:03 lipwig.qsplace.co.uk postfix/postscreen[427731]: CONNECT from [::1]:50000 to [::1]:25
Aug 15 21:13:03 lipwig.qsplace.co.uk postfix/postscreen[427731]: WHITELISTED [::1]:50000
Aug 15 21:13:03 lipwig.qsplace.co.uk postfix/smtpd[427733]: connect from lipwig.qsplace.co.uk-APISCP[::1]
Aug 15 21:13:03 lipwig.qsplace.co.uk postfix/smtpd[427733]: B942B9F946: client=lipwig.qsplace.co.uk-APISCP[::1], sasl_method=PLAIN, sasl_username=monit
Aug 15 21:13:03 lipwig.qsplace.co.uk postfix/cleanup[427755]: B942B9F946: message-id=1660594383.256051adbf8e0694@lipwig.qsplace.co.uk
Aug 15 21:13:03 lipwig.qsplace.co.uk postfix/qmgr[427730]: B942B9F946: from=, size=874, nrcpt=1 (queue active)
Aug 15 21:13:03 lipwig.qsplace.co.uk postfix/smtpd[427733]: disconnect from lipwig.qsplace.co.uk-APISCP[::1] ehlo=1 auth=1 mail=1 rcpt=1 data=1 quit=1 commands=6
Aug 15 21:13:05 lipwig.qsplace.co.uk postfix/pipe[427761]: B942B9F946: to=, relay=localmaildrop, delay=1.5, delays=0.29/0.02/0/1.2, dsn=2.0.0, statu>
Aug 15 21:13:05 lipwig.qsplace.co.uk postfix/qmgr[427730]: B942B9F946: removed

All of a sudden, everything is working again!

Work the problem! Solve one problem and then the next; And if you solve enough problems, you get to come home; or in my case fix the issue!