Not of the top of my head - but what did you change before the problem
started occurring?
I've never seen udev in conjunction with LDAP in the past, "normal"
problem points for networking & LDAP are sometimes things like
/etc/nsswitch.conf or /etc/host.conf
[edit]
And as the problem piqued my curiosity I had a brief
chat with my friend google ... ;}
http://www.mail-archive.com/debian-b.../msg77169.html
looks like his suggestion to solve your problem.
[/edit]
Cheers,
Tink