[cobbler] slow PXE boot when primary NIC unplugged

[Robert Jacobson]

I need some help with a PXE/TFTP problem.  My cobbler server has two 
NICs; the "primary" is connected to the 'net, and the secondary is 
dedicated to a deployment LAN.

DHCP and PXE/TFTP work very well when both NICs are connected.  However, 
when I disconnect the primary (internet) NIC, TFTP does some ... weird 
things

When I PXE boot a system that isn't defined in cobbler (because I want 
to just use the boot menu), the search for the boot file takes 20 
seconds between each failure:

Trying to load: pxelinux.cfg/44454c4c-4a00-1057-8035-cac04f314431
[~20 second pause...]
Trying to load: pxelinux.cfg/01-00-19-b9-cd-8c-43
[~20 second pause...]
Trying to load: pxelinux.cfg/C0A80A69
[~20 second pause...]
Trying to load: pxelinux.cfg/C0A80A6
[etc...]

(full log at http://pastebin.com/rnrzE95d)

This problem does not occur when the primary NIC is connected.  When its 
connected, it still searches, but each one immediately fails, until it 
gets to pxelinux.cfg/default -- then it gives me the menu as expected.  
The whole process takes under 1 second.

Also, if I start a PXE boot with the primary disconnected, then connect 
the primary NIC while the boot is stalled, it returns to its normal 
speedy boot.

Not sure if relevant -- In "settings" my "manage_dns" is 0.

Any ideas what is causing the delay?

-- 
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Robert Jacobson               Robert.C.Jacobson(a)nasa.gov
Lead System Admin       Solar Dynamics Observatory (SDO)
Bldg 14, E222                             [phone]