DNS server settings FC5
 

General query for the networking gurus - I found the solution but I don't know the why.

Scenario:
Home network - mixed winxx and linux - connected to internet via adsl router - netgear DG834 - all co-existing happily.

Introduce spare time, curiosity, old P3 box (gift) and Smoothwall / IPCop.

Result - tear hair out trying to get linux box working thru firewall due to DNS not working (winxx boxes OK).

Reason - DNS server info is being overridden by greyed out static IP settings in GUI (FC5 Gnome) interface specifically the gateway address see

Network device control > Configure > edit ethernet device

Solution:

Select Statically set IP addresses and remove all info in this section (all fields blank).

Reselect automatically obtain IP addresses.

Deactivate interface (downs & ups the interface with fresh DNS info) and all is fine.

Is this a FC5 only problem?? Anyone care to test with other FC releases.

If you do DHCP (non-static IP) by default it updates your /etc/resolv.conf with what the DHCP server provides. This behavior can be changed (at least in dhclient the one I had this issue on).

However if you're doing a static IP then you don't get DHCP server update at all so it doesn't overwrite your /etc/resolv.conf.

/etc/resolv.conf is the file that tells your machine what DNS server and/or domains to search when you do DNS lookups.