Just had MX record update this morning, getting Permanent Failure: 550_5.7.1_Unable_to_relay
Posted on 2006-05-21
We are migrating from a POP 3 external hosting company to internal Exchange SBS. We had the MX record updated this morning at priority 1 and now we are getting "Permanent Failure: 550_5.7.1_Unable_to_relay". We had our local ISP to the building update the PTR records as well. NSLOOKUP is still pointing at the externally hosted IP so the mail should still be working from their site, should it not? I am aware that it takes 24-48 hours to fully replicate across the DNS world at large, but if the lookup still has the old address, there shouldn't be a problem.
Am I off a bit on my assumptions?