unable to ping via hostname

[Tech_AZ]

Hello,

I have 2 domains on the same LAN but with different DNS servers.

I have 7 computers on the LAN:

Domain 1

Dom1-DC (2K3 domain controller with DNS)

Dom1-A (2K8 server)

Dom1-B (2K3 server)

Domain 2

Dom2-DC (2k3 domain controller with DNS)

Dom2-A (vista)

Dom2-B (xp)

Dom2-C (xp)

Problem:

I am unable to ping Dom1-A from Dom2-A using hostname but pinging via IP works and so does connecting via UNC: \\Dom1-A.

Pinging Dom1-DC or Dom1-B from Dom2-A works via hostname and IP.

All Domain 1 computers are configured with dynamic ip/gateway/mask but static dns.

All Domain 1 computers are configured with dynamic ip/gateway/mask but static dns.

I would greatly appreciate any help.

Thank you,