DHCP client is whatever is the default in Debian 13. DHCPd is ISC DHCPd running on a Ubiquiti EdgeRouter 4 with dnsmasq on the ER-4 also doing the DNS. The DHCP provided DNS server is a simple 10.0.0.x IP to the router and unlikely to change just preferred it to be learnt rather than hardcoding it incase in 3 years time I do and forget any overrides. Same with the IP address.
Or are you suggesting another dnsmasq on the VM and hardcoding localhost for the system? Will look into the options suggested. Nothing else is running in the VM that isn’t otherwise bundled with Debian or included in my provided install commands (iptables, postfix SPF etc).. the LAN IP is unlikely to change and even if it did a reboot wouldn’t be unreasonable. E-mail volume is tiny, I’m the only human user and this is just to run my personal email. NAS, UPS and website contact form occasionally e-mail me. Was previously running hMailServer on Windows up until a few months ago and ditched it after if was no longer maintained and iOS kept blindly IMAP PEEKing beyond the end lengths of messages causing the service to keep memory dumping (bug in the code and the original author mothballed it and I didn’t fancy compiling it or running others’ random binaries). Chose Postfix and Dovecot due to its track record in security and Debian has always been my go-to distro after running UniFi Network Server and OpenVPN servers on it for years. Thanks again both. Kind regards, Matthew > On 27 Aug 2025, at 9:11 pm, Michael Tokarev via Postfix-users > <postfix-users@postfix.org> wrote: > > On 27.08.2025 22:08, Matthew via Postfix-users wrote: >> Hi Michael, >> So cool to have a message from the actual Debian package maintainer via here >> too! > > I've been here on this list for almost 25 years :) > >> As you requested: >> root@SMTP:~# ls -l /var/spool/postfix/etc/resolv.conf >> -rw-r--r-- 1 root root 114 Aug 27 19:22 /var/spool/postfix/etc/ >> resolv.conf >> root@SMTP:~# ls -l /etc/resolv.conf >> -rw-r--r-- 1 root root 162 Aug 27 19:23 /etc/resolv.conf > > Aha. So my guess wasn't right. > >> I think it's just as simple as the service is starting too early (before >> dhcpd has concluded).. I looked more at whether network-online.target was a >> viable option and it looks like in non-GUI Trixie there's nothing that >> implements or depends on it. ChatGPT suggested some pre-script that if it >> came to it just implements a crude delay before Postfix gets started. > > Which dhcp do you use? Postfix provides hooks to update resolv.conf > but only for well-known dhcp daemons, - which aren't many in debian > these days. > > By delaying things, you wont get it fixed, - because if you'll have > different resolv.conf after next dhcp lease update, it wont be > propagated, but should. > > At this point, there are several options available. I'd suggest to > follow advice by Wietse and un-chroot at least services in question. > > In debian we ship postfix-resolvconf.path unit which can be used to > update in-chroot resolv.conf when /etc/resolv.conf changes, you can > enable it. > > Depending on your email volume, it might be a good idea to run local > caching nameserver - even something as simple as dnsmasq would do, > systemd-resolved works, unbound, or bind9. That'd be 3rd option. > > Thanks, > > /mjt > > _______________________________________________ > Postfix-users mailing list -- postfix-users@postfix.org > To unsubscribe send an email to postfix-users-le...@postfix.org _______________________________________________ Postfix-users mailing list -- postfix-users@postfix.org To unsubscribe send an email to postfix-users-le...@postfix.org
