Forgetting Computers!

[Dogers]

We use our bordermanager server to create a DMZ, where a machine with ADSL sits, among others..

Every so often, computers on the safe network will no longer be able to access the ADSL machine, everything just times out - all the other machines in the DMZ are fine, however. The BM machine itself can ping the ADSL machine when this happens, which baffles me. All the other machines in the DMZ can ping it also.

The ADSL machine is running win2kpro (ive reinstalled this machine twice now) and looking at its network connection properties, it appears to receive the connection/ping attempts from the computers in the safe network, but just does not respond. If the network connection is disabled and then re-enabled, all is fine! (Rebooting the machine, oddly enough, DOESNT fix it). I've tried enabling its onboard lan (currently it has a 3com card) which exhibits the same problem. I've also tried both on different ip addresses, again, still with the same problem..

I'm beginning to wonder if the BM machine could be at fault, so short of me replacing the whole ADSL machine with another one (oh yeah, ive replaced the hub which serves the DMZ - same problem still) - is there anything i can try on the BM machine for diagnostics as to whats happening to the packets?? (or any other idea at all?!)

 

[Dogers]

well, i've investigated some more, and it appears bordermanager is innocent, although i still have my doubts

have totally replaced the adsl machine now, and so far, so good..

still dont know why the previous machine would completely ignore an entire subnet every so often though!

 

[Provogeek]

Odd issue you have there, may be related to routing.

To view all the packets that go through the BM server use this console command SET TCP DEBUG = 1 This dumps all incoming and outgoing packets processed by the TCPIP.NLM. You only see packet information, you won't see packet data (get a sniffer for that). Setting it to zero will turn it off. Now this goes to console, so you will need to use the conlog to find what your looking for.

But to find the problem, look at the ADSL machines default gateway and make sure that gateway has a route to your BorderManager server and the BorderManager server has a route to your internal network (which it should if you only have a single internal subnet).

Provogeek

Saving the world, one network at a time

 

[Dogers]

i'll give that a go - i believe it wasnt the machine at fault now, as i've just installed Win2k SP3 on the replacement machine and its started doing it again..! time to search on MSKB

 

[Dogers]

erm, i cant set that! it doesnt know TCP DEBUG, "TCP DEBUG" or TCPDEBUG ?

cant seem to find it in the list of settable options either..

 

[Provogeek]

Sorry, it's SET TCP IP DEBUG = 1

Provogeek

Saving the world, one network at a time