I have an intermittent problem with our external mail.
During the course of the day our external emails stop working. If I look at the SMTP queues in exchange there will be a number of messages in a "messages with unreachable destination queue". If I try and telnet our isp's mail queue mta.xtra.co.nz 25 I will receive a connection to host failed. But if I telnet from out ISA server it works fine.
These outages last between 4 to 7 hours and start working again without me doing anything. And some days I have no outages at all.
Our system had been working fine for 2 years until now. And I have made no changes to our exchange server or our ISA server.
Any advice would be greatly appreciated.
During the course of the day our external emails stop working. If I look at the SMTP queues in exchange there will be a number of messages in a "messages with unreachable destination queue". If I try and telnet our isp's mail queue mta.xtra.co.nz 25 I will receive a connection to host failed. But if I telnet from out ISA server it works fine.
These outages last between 4 to 7 hours and start working again without me doing anything. And some days I have no outages at all.
Our system had been working fine for 2 years until now. And I have made no changes to our exchange server or our ISA server.
Any advice would be greatly appreciated.
