i have a newly loaded server standard 2008 r2 setup and running like a charm, apart from one problem, at random times we stop recieving mail and then i see when i ping this mail host it doe snot respond from any client pc in the network, however this mail does respond when i ping it from the domain controller running server 2008 standard and dc, dns.
why would my users stop having access to this mail host at random times ? the mail is down for about 5 -15 minutes at a time, and comes back online by itself , i have confirmed that the ISP where the mail server is hosted, has put me on all the whitelists, on their side, as well as phoned my ISP to see if my link is not maxing out or flapping - and they say no, the link is running at less than half its capacity most of the time.
so now i dont understand why ? i have 2 layer 2 3com switches which has nog special configs on them,
i have a feeling it might be a trust issue between this mail host that runs exim smtp and my newly created domain controller but i am not sure, can anyone point me in the right direction of why i would be able to ping this mail host perfectly from the server but it times out randomly for periods of up to 15 minutes at a time from any client pc of the network ?