We are having a serious problem sending mail out from our Exchange server. We have Exchange 2007, fully patched, running on Server 2003 R2, again, fully patched.
The problem started Thursday when it was noted that some e-mail was not going out, but sitting in the queues. The message give was ""421 4.4.2 Connection dropped.' Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts." A check showed that we were listed on an RBL, NOMOREFUNN which apparently blocks whole ranges of IP addresses--checking showed that the whole class C network we are part of was blocked by them. I applied for a removal of the block, but it never happened, and now that RBL is timing out when I try to check it using MXToolbox, but I can reach it manually, and, despite the requests, it still shows us as being on the list. Their complaint is " washdc.fios.verizon.net. Dynamic IP or generic rDNS". It does appear that there is a generic rDNS right now, which there did not used to be. I have talked to Verizon about getting this fixed, but I do not think this is the source of the problem, since whether the mail goes through is a hit or miss affair. I do not believe that NOMOREFUNN is a widely used RBL, and do not think it is a source of the problem, however, it may be that the rDNS is. Am I going the right way with this, or am I barking up the wrong tree and fixing the rDNS will not fix the problems we are having? -- \\Steve//
