Additionally, RFC 2821 was designed to replace RFC 821. Their behavior breaks RFC 821. Guess who was behind RFC 2821? EarthLink. John T eServices For You -----Original Message----- From: John Tolmachoff (Lists) [mailto:johnlist@xxxxxxxxxxxxxxxxxxx] Sent: Monday, April 11, 2005 9:34 AM To: [ExchangeList] Subject: [exchangelist] RE: Cannot Send To Earthlink http://www.MSExchange.org/ Ah, the Earthlink DNS problem. Yes, it is their problem. For some reason, when their servers listed in the MX records are not available or busy, they do not correctly respond with a 4.4.x code, meaning there is a temporary problem and try again later, they do not respond at all. So, then the sending e-mail server will CORRECTLY according to RFC look up an A record and attempt to send to that IP. That IP then gives a 5.x error and you get the resulting bounce. Earthlink needs to fix their problem by correctly responding with a 4.4.x code when their servers are busy instead of trying to push on every one their crap about RFC 2821. Additionally, their A record should not be responding to SMTP at all if that is the way they are going to configure their DNS records. If their A record was not responding to an SMTP request, the all would be fine as the sending server would then record a failure to connect and requeue the message for later delivery. John T eServices For You -----Original Message----- From: Lloyd Williams [mailto:Williams@xxxxxxxxxxxxxxxxxxxxxxx] Sent: Monday, April 11, 2005 8:45 AM To: [ExchangeList] Subject: [exchangelist] RE: Cannot Send To Earthlink http://www.MSExchange.org/ Hi I originally posted the question. I have now resolved it. I too initially thought the problem was a reverse DNS lookup issue; however, it was something else. It is described in the following link http://www.webservertalk.com/archive130-2004-1-90695.html In a nut shell the problem was solved by switching the DNS my SMTP connector uses to an external DNS. The problem was caused by my internal DNS somehow switching from using the EarthLink MX record to using the EarthLink A record Lloyd _____ From: Scheele, Brian [mailto:bscheele@xxxxxxxxxxxxxxx] Sent: Monday, April 11, 2005 11:21 AM To: [ExchangeList] Subject: [exchangelist] RE: Cannot Send To Earthlink http://www.MSExchange.org/ I did not see the original question, but thought this might be helpful to some: Earthlink will block any email from any server that does not have reverse dns properly configured. For example, Sprint currently does not support setting up reverse dns properly for their ADSL customers, so we have to forward our email through a smarthost. Since Earthlink and Sprint are partners with DSL, Sprint directed me to have Exchange send all email to smtp.earthlink.net. This resolved our email issue. We have Symantec Mail Security for SMTP Gateways, which will allow us to route through the smarthose for only those destinations that we have problems with. This allows us to use DNS for everyone else that normally works. There are other programs out there that will do the same thing. Do not try to contact earthlink about any email issues since most of their tech support is clueless. Thanks, Brian Scheele Systems Administrator Clark Filter 3649 Hempland Road Lancaster, PA 17601-1393 Ph: 717.285.5941 x176 Fx: 717.285.3039 ..org ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=exchangelist Exchange Newsletters: http://www.msexchange.org/pages/newsletter.asp Exchange FAQ: http://www.msexchange.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Other Internet Software Marketing Sites: World of Windows Networking: http://www.windowsnetworking.com Leading Network Software Directory: http://www.serverfiles.com No.1 ISA Server Resource Site: http://www.isaserver.org Windows Security Resource Site: http://www.windowsecurity.com/ Network Security Library: http://www.secinf.net/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this MSEXchange.org Discussion List as: johnlist@xxxxxxxxxxxxxxxxxxx To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=exchangelist Report abuse to listadmin@xxxxxxxxxxxxxx ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=exchangelist Exchange Newsletters: http://www.msexchange.org/pages/newsletter.asp Exchange FAQ: http://www.msexchange.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Other Internet Software Marketing Sites: World of Windows Networking: http://www.windowsnetworking.com Leading Network Software Directory: http://www.serverfiles.com No.1 ISA Server Resource Site: http://www.isaserver.org Windows Security Resource Site: http://www.windowsecurity.com/ Network Security Library: http://www.secinf.net/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this MSEXchange.org Discussion List as: johnlist@xxxxxxxxxxxxxxxxxxx To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=exchangelist Report abuse to listadmin@xxxxxxxxxxxxxx