Hello,I have a client that intermitently receives the following response from my Exchange server during helo:helo mail.xxx.com (10.10.10.10) - ClientHi I am smtp.xxx.com (64.64.64.64) - Our Exchange server responseSeveral things bug me about this issue. First is that the problem seems to be intermitent and I have only had problems with this one client. Second, this only happens when the sending gateway attempts to do a reverse lookup to authenticate my Exchange server. Third, how do I make the responses consistent? I would like to modify the response so it responds with hi I am mail.xxx.com (10.10.10.10) no matter how the outside world is trying to authenticate. Unless I can accomodate this change this particular client will continue to have mixed success sending email to my organization. Any assistance would be appreciated.Thanks,Alan

What application is the client computer (Lotus Notes, Edge Server, HUB server, etc) and where does this client sit (inside your network outside your network, in the DMZ, etc). Can you also post the SMTP comunication so I can get a better understanding of the error occuring?Thanks ChrisChristopher C

I see I was a little vague. Apparently my client uses a Barracuda gateway device (DMZ) that doesn't keep the details if the communication fails. I think that this may be something as simple as a banner issue? Here is the telnet output: “telnet mail.xxx.com 25” Then get: “220 smtp.xxx.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at Tue, 13 Oct 2009 15:51:31 -0500”Is it possible that the gateway device is reading the banner and believes that it is talking to a different host aka not a valid communication? As you can see the 220 response is different than the queried mail host. Whatever the case the Barracuda sees this as a conflict and discards the communication as not valid. I am running Exchange Server 2003 in a FE/BE configuration. The FE is in our internet DMZ.Thanks,Alan

Similar issue mentioned in below thread. Check the required Information on MX as well as RDNS side http://social.technet.microsoft.com/Forums/en-US/exchangesvradmin/thread/721d340e-0495-4c7b-97e9-a94dc094fe87/Vinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|

On Tue, 13-Oct-09 16:00:57 GMT, Al_Stu34 wrote:>Hello,>>I have a client that intermitently receives the following response from my Exchange server during helo:>>helo mail.xxx.com (10.10.10.10) - Client>Hi I am smtp.xxx.com (64.64.64.64) - Our Exchange server response>e the responses consistent? I would like to modify the response so it responds with hi I am mail.xxx.com (10.10.10.10) no matter how the outside world is trying to authenticate. Unless I can accomodate this change this particular client will continue to have mixed success sending email to my organization. Any assistance would be appreciated.How many MX records (or A records) exist for your domain name? Maybethe response isn't from your server but from a secondary MX for yourdomain?Your SMTP protocol logs should show you the response your server sends(for Exchange 2007 -- 2003 only shows the HELO\EHLO and the status,but not the data it sends). A network monitor (with the appropriatecapture filter) would show you all the traffic to/from the otherserver's IP address.Why would the other server do a reverse lookup when it's the oneinitiating the connection? It only makes sense to look up the IPaddress when receiving a connection, not when initiating one.---Rich Matheisen Exchange MVP--- Rich Matheisen MCSE+I, Exchange MVP

On Tue, 13-Oct-09 21:03:59 GMT, Al_Stu34 wrote:>I see I was a little vague. Apparently my client uses a Barracuda gateway device (DMZ) that doesn't keep the details if the communication fails. I think that this may be something as simple as a banner issue? Here is the telnet output:>>>> ?telnet mail.xxx.com 25? >> Then get: ?220 smtp.xxx.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at Tue, 13 Oct 2009 15:51:31 -0500?> believes that it is talking to a different host aka not a valid communication? As you can see the 220 response is different than the queried mail host. Whatever the case the Barracuda sees this as a conflict and discards the communication as not valid. I am running Exchange Server 2003 in a FE/BE configuration. The FE is in our internet DMZ.Is your domain "mail.xxx.com" or "xxx.com"? If it's "xxx.com" then youmay have several MX records (or one MX and several A records, orseveral MX AND several A records) and, assuming that each of the SMTPservers puts their FQDN into the 220 banner it's perfectly acceptableto get a different FQDN every time you connect to a SMTP server inyour domain. So a mismatch in the DOMAIN name and the FQDN is prettynormal.---Rich MatheisenMCSE+I, Exchange MVP--- Rich Matheisen MCSE+I, Exchange MVP

Thanks. I can see I have a lot to learn.