[exim] A problem with time outs to and from Exchange 5.0?

We're running 4.50 (on Debian) (recently upgraded from 4.43).

We're having a problem with sending/receiving from a couple Exchange servers (both version 5.0 (specifically, 5.0.2195.6713).

Yesterday, we could send to them, but they would get time outs sending to us. But today, we're getting timeouts sending to them.

Has anyone seen that problem before? Those are the only two servers we're having a problem sending to and I don't know if it is something to do with that specific version of Exchange and Exim 4.50 or what. Does anyone have any ideas on what I should check?


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