On Sat, Jul 27, 2019, 22:35 Wietse Venema <wie...@porcupine.org> wrote: > > Mantas Mikul?nas: > > Disregard this; I'm sure I have found the nss module that causes high > > memory usage. > > Which nss module would that be?
It was libnss_myhostname (specifically the version that is included with systemd). Besides handling the system hostname as advertised, the systemd-bundled variant also recognizes the magic hostname "_gateway" and resolves it to wherever the OS default routes point, and the other way around. So whenever Postfix does a reverse-DNS lookup and the regular "files"/"dns" modules yield no result, the "myhostname" module scans all routing tables to compare the query against the default gateways, leaking a bit of memory after doing so. > Postfix does not care how many routes > a system has, but it does care about local network interface addresses > and netmasks if main.cf:mynetworks does not specify those explicitly. > > Wietse
