hello all , 

i have problem with webmail , the issue is this 

i have to site A and B , we got problem with power ( failure )  on the DMZ switch of site A , now site B are using the exchange of site A , when trying to access the webmail from site B it is not working i.e. when trying to access mail.A.com from site B not working  , but i can access the mail.A.com from anywhere except site B

when trying to telnet mail.A.com from B site on port 25 it is not working 

when trying to telnet mail.X.com or any other webmail  from B site on port it is working fine .

any one can help please .