'Postfix chroot dns resolve problem (Ubuntu 18.04.4 LTS, Postfix 3.3.0)
I have a Postfix setup configured with chroot=y in master.cf file(full original config). When the chroot is enabled, the DNS resolvation not work (the sender is from valid, popular service): "postfix/smtpd[19114]: connect from unknown[X.X.X.X]"
Possible solutions that i tried:
- copy /lib/x86_64-linux-gnu/libnss_* and needed lib files to the jail(/var/spool/postfix/...)
- with systemd-resolved and replaced with resolvconf package (for testing)
- static /etc/resolv.conf (not /run/systemd/system/resolv.conf symlink)
- various possibilites in nsswitch.conf
The hosts file is working in chroot mode, i've tested with static entries.
Any other possible solutions?
Thanks for the help.
Z
Solution 1:[1]
Ive found the solution.
If your system run ZFS or have any separated partitions (like /var/spool), than you need to make sure that partion (where is the postfix chroot) have exec rights.
Defaults are usually enough for the ext4 file system, zfs need exec flag.
Solution 2:[2]
Running /usr/lib/postfix/configure-instance.sh will copy library and config files needed for chroot to /var/spool/postfix.
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | So.Zoltan |
| Solution 2 | Saustrup |