Table of Contents
Network Performance Issues (Linux)
Some things to try when you have network performance problems in Linux.
Slow DNS Lookups
Update: The problem returned, even with the nsswitch.conf change in place. 
Symptoms: On some (not necessarily all) websites, you'll see a delay of several seconds on the “Looking up…” message in Firefox.
I first tried the obvious step of checking/changing my DNS server addresses, but this didn't help. I resolved the issue by changing the “hosts” line in /etc/nsswitch.conf.
#hosts: files mdns4_minimal [NOTFOUND=return] dns # original line hosts: files dns # changed to this