Win2003 Enterprise Domain Controller

[Ed Cox]

Strange problem...
Blade 1 is the DC and it can ping Blade 2 (also running 2003 Ent). But Blade 2 can't ping Blade 1. No firewalls, DHCP, ICS or ISA installed on DC.
Google searching keeps pointing to DNS.

Blade 1 was pointed to an ISP for DNS during AD installation. Changed that back to local DNS. Blade 2 points to Blade 1 as it's DNS server. I cannot figure out why Blade 2 can't ping Blade 1.
Blade 1 (DC) IP config is pointing to itself as gateway and DNS.
Removed DNS, rebooted, re-installed DNS, rebooted...still no luck.
Any thoughts? It might be switch related (GbE-2), not sure yet. We might try swapping the DC to a different slot. But the switch is factory fresh with no addtional setup by us. One big happy VLAN. All ports should be untagged.
Thanks!!
Ed

[Ivan Ferreira]

Are Blade 1 and Blade 2 on the same subnet?
Have the subnet mask correct?
There is no IP filter on the network interface advanced properties?
Have you enabled ipsec?
Use netcap or network monitor to verify what packets are going from/to your servers.
Can you ping blade 1 from another system?

[Ed Cox]

Hello Ivan,

Are Blade 1 and Blade 2 on the same subnet?
Yes
Have the subnet mask correct?
Yes
There is no IP filter on the network interface advanced properties?
No
Have you enabled ipsec? We made sure the service was stopped - should we disable this feature in the meantime? If so...I have forgotten how to disable IPSec! :(

Use netcap or network monitor to verify what packets are going from/to your servers.
We might give that a shot.

Can you ping blade 1 from another system?
No ...we put a notebook on the same subnet and we were able to ping the notebook from the DC but the notebook could not ping back to the DC.

Thanks for the response.
Ed

[Ivan Ferreira]

Ensure that you don't have duplicate ip address on you network. Use pathping to test the connectivity.

Check the route print output.