A little warning about this. If you are doing any kind of RBL or other DNS-based spam filtering, and you are set to use an upstream DNS server, you may run into problems with the quantity of DNS lookups on their server. I had this setup once and was contacted by my ISP. They said I was doing something like 30,000 lookups on their server an hour and could I please stop or have my service suspended. Using an upstream DNS server in this manner amounts to a DOS on their server.
YMMV Dan Horne -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Katie LaSalle-Lowery Sent: Wednesday, June 01, 2005 1:29 PM To: [email protected] Subject: RE: [IMail Forum] MX problem has me stumped Okay... Changing to an upstream provider's DNS server did the trick. So, apparently something somewhere in the house is messed up. I'll move on to clearing every cache we have even if they look good. Thanks, Katie -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Katie LaSalle-Lowery Sent: Wednesday, June 01, 2005 11:11 AM To: [email protected] Subject: RE: [IMail Forum] MX problem has me stumped Well, I entered a different DNS server in Iadmin SMTP settings and restarted SMTP & Queue Manager. I didn't get the same results. However, I still didn't get good results. It's still finding the wrong server. It's just finding a different wrong server now. I'll try a DNS server from an upstream provider and see if the results are any different. I did check that all DNS servers in our organization either don't have hcpglobal.com cached or, if it is in the cache, that the records match what I get looking up at www.dnsstuff.com. I have Imail set to not cache DNS. However, I do wonder about that... It wouldn't be the first time that what was really happening was not what was set in the Iadmin screen. Specifically, I struggled with the Webmail timeout issue for ages before finally using a search query at the KB that got me the info about duplicate files and the wrong one being modified. Now that I'm thinking about that I wonder if maybe I should dig up that article again and see if all of the changes I'm making in Iadmin with regard to DNS are for naught (which I seem to be having trouble doing now so if anyone has the KB Article # handy I'd be grateful--seems I failed to save that article). However, that the results changed suggests that something changed, just didn't change exactly how I was hoping. This one continues to stump me. ~Katie -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Eric Shanbrom Sent: Tuesday, May 31, 2005 6:59 PM To: [email protected] Subject: Re: [IMail Forum] MX problem has me stumped The log shows the answer. For some reason you are not getting a DNS response to the query 20050527 165031 127.0.0.1 SMTP (09C0E182) [x] looking up hcptravel.com by stack When this happens you will get the address that the domain resolves to (in most cases it will be their web server) which if it has a mail server running on it most likely will not accept mail for the users of the domain 20050527 165055 127.0.0.1 SMTP (09C0E182) 553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1) I would try a different DNS and see if you get the same results Eric S Katie LaSalle-Lowery wrote: >Hi there, > >Setup info: >Imail 8.05 running on MS Windows Server 2003 using DNS from another MS >Windows Server 2003 which, in turn, uses our primary DNS server as its >forwarder. Our primary DNS server is running Simple DNS v4. > >I've got an ongoing problem wherein my users can't send email to a >particular domain (hcptravel.com). > >What we have found is that if the user addresses the message using the >mail server's A record rather an MX the message is delivered (i.e. if >the message is addressed to [EMAIL PROTECTED] instead of [EMAIL PROTECTED]). > >I have cleared the Imail DNS cache and even turned it off (and >restarted Queue Manager and SMTP). I have also cleared the cache on >the DNS server that the Imail server uses. > >When mail is addressed to [EMAIL PROTECTED] the undeliverable response >says unknown user. So, it appears it's not failing to resolve to a >mail server but rather is resolving to the wrong mail server. > >A trip through the log shows: > >20050527 165012 127.0.0.1 SMTP (09C0E182) [x] looking up hcptravel.com >in HOSTS and MX >20050527 165031 127.0.0.1 SMTP (09C0E182) [x] looking up hcptravel.com >by stack >20050527 165037 127.0.0.1 SMTP (09C0E182) Trying hcptravel.com (0) >20050527 165037 127.0.0.1 SMTP (09C0E182) [x] Connecting socket to >service <SMTP> on host <hcptravel.com> using protocol <tcp> >20050527 165037 127.0.0.1 SMTP (09C0E182) [x] using source IP for >mail.centric.net [69.51.66.6] >20050527 165055 127.0.0.1 SMTP (09C0E182) Connect hcptravel.com >[209.209.30.31:25] (2) >0050527 165055 127.0.0.1 SMTP (09C0E182) 220 >mail.ucsbgauchogetaways.com ESMTP >20050527 165055 127.0.0.1 SMTP (09C0E182) >EHLO mail.centric.net >20050527 165055 127.0.0.1 SMTP (09C0E182) >250-mail.ucsbgauchogetaways.com >20050527 165055 127.0.0.1 SMTP (09C0E182) 250-PIPELINING >20050527 165055 127.0.0.1 SMTP (09C0E182) 250 8BITMIME >20050527 165055 127.0.0.1 SMTP (09C0E182) >MAIL >FROM:<[EMAIL PROTECTED]> >20050527 165055 127.0.0.1 SMTP (09C0E182) 250 ok >20050527 165055 127.0.0.1 SMTP (09C0E182) >RCPT >To:<[EMAIL PROTECTED]> >20050527 165055 127.0.0.1 SMTP (09C0E182) 553 sorry, that domain isn't >in my list of allowed rcpthosts (#5.7.1) >20050527 165055 127.0.0.1 SMTP (09C0E182) >QUIT >20050527 165055 127.0.0.1 SMTP (09C0E182) 221 >mail.ucsbgauchogetaways.com >20050527 165055 127.0.0.1 SMTP (09C0E182) [u] closing socket (u) >20050527 165055 127.0.0.1 SMTP (09C0E182) Creating message from >Postmaster > >Yep, definitely the wrong server. > >When I looked at the cache on the MS Windows Server 2003 server the >cache didn't have a record for hcptravel.com. I did an nslookup, >refreshed and looked at what had gotten cached. It had cached the MX >for hcptravel.com as hcpms1.hcptravel.com and the IP for that as 216.101.248.130. That's right. >The Imail server uses that Windows Server 2003 server for DNS. > >At this point, everything looked good as far as DNS so I tried another >test email. (I'm using the address [EMAIL PROTECTED]) > >0050531 114018 127.0.0.1 SMTP (09C06185) Stack connect fail >"209.209.30.30" >20050531 114018 127.0.0.1 SMTP (09C06185) Connect hcptravel.com >[209.209.30.31:25] (2) >20050531 114018 127.0.0.1 SMTP (09C06185) 220 >mail.ucsbgauchogetaways.com ESMTP >20050531 114018 127.0.0.1 SMTP (09C06185) >EHLO mail.wkaehlerphoto.com >20050531 114018 127.0.0.1 SMTP (09C06185) >250-mail.ucsbgauchogetaways.com >20050531 114018 127.0.0.1 SMTP (09C06185) 250-PIPELINING >20050531 114018 127.0.0.1 SMTP (09C06185) 250 8BITMIME >20050531 114018 127.0.0.1 SMTP (09C06185) >MAIL >FROM:<[EMAIL PROTECTED]> >20050531 114018 127.0.0.1 SMTP (09C06185) 250 ok >20050531 114018 127.0.0.1 SMTP (09C06185) >RCPT >To:<[EMAIL PROTECTED]> >20050531 114018 127.0.0.1 SMTP (09C06185) 553 sorry, that domain isn't >in my list of allowed rcpthosts (#5.7.1) >20050531 114018 127.0.0.1 SMTP (09C06185) >QUIT >20050531 114018 127.0.0.1 SMTP (09C06185) 221 >mail.ucsbgauchogetaways.com >20050531 114018 127.0.0.1 SMTP (09C06185) [u] closing socket (u) >20050531 114018 127.0.0.1 SMTP (09C06185) Creating message from >Postmaster > >It's still connecting to the wrong mail server. > >Any suggestions as to what I'm missing here? > >Thanks, >Katie LaSalle-Lowery >Centric Internet Services >1410 Reserve St. >Missoula, MT 59801 >Local Phone 549-3337 ext. 21 >Toll Free (888)593-2776 ext. 21 >Fax (406)721-3438 > > > > > > > > > > > > > > > >To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html >List Archive: >http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ >Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ > > To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
