Weird kickstart problem regarding not selecting the right cfg

[Ben]

We recently acquired four new machines (Sun X4270s).  As usual as I've done 
with dozens of other machines I constructed RHEL5 kickstart .cfg files for 
them and made additions to the syslinux.cfg of the form:

label ct-phy-dom01
   kernel vmli5s64
   append initrd=int5s64.img ks=hd:sdb1:/configs/ct-phy-dom01.cfg console=ttyS0,9600
label ct-phy-dom02
   kernel vmli5s64
   append initrd=int5s64.img ks=hd:sdb1:/configs/ct-phy-dom02.cfg console=ttyS0,9600
label ct-phy-dom03
   kernel vmli5s64
   append initrd=int5s64.img ks=hd:sdb1:/configs/ct-phy-dom03.cfg console=ttyS0,9600
label ct-phy-dom04
   kernel vmli5s64
   append initrd=int5s64.img ks=hd:sdb1:/configs/ct-phy-dom04.cfg console=ttyS0,9600

# vmli5s64 = vmlinuz for RHEL5, server, 64bit
# int5s64.img = initrd.img for RHEL5, server, 64bit
# (note that the name of the initrd file must conform to 8.3 rules, just 
# like in DOS or it doesn't work!)

I placed the machine-specific .cfg files and the syslinux.cfg on a USB stick 
as we do for certain installs and powered the first machine (ct-phy-dom01) 
on.  After typing "ct-phy-dom01" at the boot: line the machine installed via 
HTTP perfectly.  However after that all the other machines failed to 
install.  After watching ct-phy-dom02-4 repeatedly stop at the point at 
which they should load stage2.img from the HTTP server I theorised it was 
something to do with the network.  Cue over an hour of network testing, 
changing cables, checking VLANs and adding ksdevice=<MAC address of chosen 
NIC in the server> to the syslinux.cfg.  Nothing worked.  At no point could 
I ping the IP (in the ks.cfg) of the box I was installing.

Eventually, even though I was booting via serial I plugged in a monitor and 
paged through the other virtual consoles and noticed that at install the 
machines were all selecting the ct-phy-dom01.cfg file despite what the 
syslinux.cfg specified.  Obviously this meant they were trying to raise the 
IP of ct-phy-dom01 which had already been built and was up and running.

No matter what I tried I could not get any of the other machines 
(ct-phy-dom02-04) to use their own cfg files until I started commenting out 
the lines of servers I wasn't building in syslinux.cfg.  Want to build 
ct-phy-dom02?  Comment out ct-phy-dom01's lines.  ct-phy-dom03?  Comment out 
ct-phy-dom01 _and_ ct-phy-dom02.  Etc.

Now, can anyone explain why?

Ben
-- 
Unix Support, MISD, University of Cambridge, England
Plugger of wire, typer of keyboard, imparter of Clue
         Life Is Short.          It's All Good.