FC5 locks when DNS goes down
 

When my ISP's DNS servers go down FC5 hangs for long periods during bootup and Gnome won't even open a terminal window if already logged in when it happens. Ctrl-Alt-F1 then ifdown eth0 is only way to make system responsive again.

Isn't there some kind of default DNS lookup timeout value? Doesn't appear to be IMHO.

There is a timeout for each DNS, so if you specify three, that's three timeouts. If you are using DHCP, then DHCP retries several times, each time going through the timeout cycle.

If your ISP DNS is that unreliable (very strange), you can specify a public DNS server as your secondary or tertiary DNS.

Well, then whatever the timeout value is it's way too high. How can I adjust it?

There are a few things you can do to reduce timeouts.

1- If you are not using IPv6, in /etc/modprobe.conf add:

alias net-pf-10 off
alias ipv6 off

2- in /etc/resolv.conf, add:

option timeout:1

3- Edit /etc/sysconfig/network, and add:

DHCP_TIMEOUT=2

Note that by setting these values low, slow servers may timeout instead of having an opportunity to respond.

FC5 hangs when DNS server not available.
 

In your /etc/hosts file make sure you have added the real host name for the local box. This allows the local box to resolve it's own name and may help eleviate the problem. Otherwise you can run a local DNS server that syncs with a public server. When your DSL goes down you.