Two puzzling XP workgroup networking problems

[John Gray]

A local charity has a workgroup containing four XP PCs, ethernetically connected to the router. Most things work happily, but...

Problem 1: whichever PC is chosen, pinging PC04 from it returns an IP address of 127.0.0.1

Problem 2: one PC has the name PC03, but PINGing PC03 from any PC fails with the usual Not found message, as if it had a different name. In fact, running WakeMeOnLAN shows all the PCs bar one with different names, yet PCs 01, 02 and 04 can be PINGed successfully.

In passing I note that I can access a share called Backup$ which exists on each PC as \\PCnn\Backup$.

Any suggestions would be very useful so I can try them when I return next Thursday. Thanks!

[StuartR]

Do you know how the PC's are translating names to IP addresses?

I assume you know that 127.0.0.1 is the loopback address that a PC uses when talking to itself, so that suggests that each PC thinks PC04 is a reference to the local computer. You might want to check the contents of the hosts and lmhosts files to see if there is something incorrect there.

This technet article is pretty long, but it is well worth reading the bit that starts Configuring TCP/IP Name Resolution

[John Gray]

I would imagine "in the usual way", whatever that is!

Neither hosts nor lmhosts had been changed from the original install on the computer I looked at, and so effectively contains no settings.
This is yet another of the things which puzzled me.

I will look through your suggested article, and try removing/re-adding PCs from/to the workgroup.

[StuartR]

It would be interesting to see what output you get from the DOS command
NSLOOKUP PC04
on each of the PCs

Also the output of
nbtstat -n
which shows the netbios name table

[John Gray]

Thanks, I'll add those to the list for Thursday.

[John Gray]

The two problems mentioned in my first post have been resolved (mostly) by

a) determining that the router's DNS was assigning a 127.0.0.1 address, as well as the correct 192.168.1.xx, to PC03. This router (BT2700HGV) won't let you remove DNS-resolved system entries, but a router reboot caused the 127.0.0.1 address to disappear from the DNS table. Really quite unimpressive for a router to be so stupid.

b) renaming PC04 and putting it into a dummy workgroup, rebooting, then setting the PC name and workgroup back to the original, and rebooting.

Thanks, Stuart, for your suggestions (you can have the NSLOOKUP and NBTSTAT -n info if you want!).

[StuartR]

...Thanks, Stuart, for your suggestions (you can have the NSLOOKUP and NBTSTAT -n info if you want!).

Don't need them now you've fixed it. That sounds like a pretty dumb (or buggy) router to me. I'm glad you managed to sort it out.