Not having a high enought default soft limit in /var/qmail/control/conf-common caused the qmail-pop3d and qmail-smtpd to not be able to load libnss and get the port from the service name. Adding strace to the call provided: @40000000404077a910b6d0f4 open("/lib/libnss_files.so.2", O_RDONLY) = 3 @40000000404077a910b7694c read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\300%\0\0"..., 640) = 640 @40000000404077a910b824cc fstat(3, {st_mode=S_IFREG|0755, st_size=42568, ...}) = 0 @40000000404077a910b91ecc mmap(NULL, 1089000, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = -1 ENOMEM (Cannot allocate memory) @40000000404077a910b9ab6c close(3) = 0 @40000000404077a910ba303c munmap(0x2a9556b000, 26443) = 0 @40000000404077a910baf774 write(2, "tcpserver: fatal: unable to figu"..., 60tcpserver: fatal: unable to figure out port number for smtp Reproducible: Always Steps to Reproduce:
so increase the soft limit in /var/qmail/control/conf-common
