The system function gethostbyname() failed to find the client's host name

As we are facing issue with this server connection. The error is:
The system function gethostbyname() failed to find the client's host name.

how can i check if the server "server1" is able to resolve the client hostname (hosts / dns)?

i can ping the client from server.

any idea with regards to the error?

Thanks

---------- Post updated at 01:04 PM ---------- Previous update was at 01:02 PM ----------

btw the master server is a linux server and the client is a solaris server

Has this ever worked? What was the h_errno value?