IP segment change from 192.168.0.0 to 192.168.10.0

Hello,
hopefully somebody know the system better than me (and this is sure :-).
The question is, is there a summery which variables need to set to ensure the server runs well?

I did change the followed variables:
interfaces/eth0/address 192.168.0.3 → 192.168.10.3
dns/forwarder2 192.168.0.1 → 192.168.10.1
gateway 192.168.0.1 → 192.168.10.1
dns/allow/query/cache localhost; 10.0.0.0/8; 169.254.0.0/16; 172.16.0.0/12; 192.168.0.0/16; fc00::/7; fe80::/10; localnets → localhost; 10.0.0.0/8; 169.254.0.0/16; 172.16.0.0/12; 192.168.10.0/16; fc00::/7; fe80::/10; localnets

But the topic is, that after change I can’t receive and sent mails (receive by pop3) I get followed message:

Feb 24 21:06:34 mail fetchmail[1608]: konnte kanonischen DNS-Namen von pop.gmx.net (pop.gmx.net) nicht finden: Temporärer Fehler bei der Namensauflösung

PS.: Router is for sure set from 192.168.0.1 → 192.168.10.1

Thx for any hint what goes wrong.