[CentOS] The most weird thing i've ever seen (networking)

[Chris Boyd]

On Mar 4, 2007, at 7:01 PM, Radu-Cristian FOTESCU wrote:

> What have a Cisco switch and the DHCP to do
> with an interface not coming up at all?!

Some Cisco switches take a long time to negotiate link speed, duplex,  
and bridge forwarding when left at default settings.  This causes the  
initial DHCP requests to time out, leaving you with no IP address as  
the box comes up.  dhclient should finally run again and get an  
address, but it can take a few minutes.

You can speed this up by using the "portfast" keyword, but do be  
careful and read up on it before enabling it.  Portfast on the wrong  
port can cause a network meltdown.

--Chris