Yes I agree, if there is a lookup failure it should fail immediately. Also if the DNS lookup is ok, and Xmail cannot connect to the IP address, it should fail immediately.
Now I hear you say, no!!! This is the correct function. This is why the RFCs call for a secondary email server on a separate class C. Although the separate class C bit is out of date due to CIDR and subnetting. But when the primary MX is uncontactable, an MTA should try the other MXs in order until exhausted. If no response from any of them, then 5xx error, immediate NDR. If any of the MXs communicate on port 25, but return an error, then that would be a 4xx error, or what ever error they issue. Rob :-) -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of CLEMENT Francis Sent: Friday, March 03, 2006 8:11 PM To: '[email protected]' Subject: [xmail] Xmail 1.22 retries on 'no existing domains' email addresses ! After the thread related to "Xmail 1.22 retries on 'bad' email addresses !" (in fact syntax error on domain fqdn in recipent email address) we conducted a survey to our xmail servers to potential mail delay, mail lost, configuration problem, .... At this time, we discovered another 'strange' think : It seems that xmail also retries and retries til last attempt before returning a NDR on effectively no existing domains (not due to syntax error in dom name, ...) (notice that actually the ndr is finaly send to sender witch is the good result, but with long delay, not immediatly, so the problem is just in this delayed ndr response) A nslookup to the recipient domain name effectively returns a 'no existing domain' (so using local dns servers). My xmail servers setup : XMail 1.22 on W2K SP4 (Win32) W2K ip stack configured to use local dns servers (Microsoft Dns servers) Xmail set to NOT use 'smartdnshost' (line commented in server.tab file) so Xmail uses its own 'resolver' and never use local resolver (I think ...) Here is a slog on a test message ( "noexistingdomainname.com" really don't exist at this time, try it with nslookup/dig, a send a mail to '[EMAIL PROTECTED]' and wait for the ndr response from xmail) Strange think is that internaly generated, xmail SMTP-Error shown in the slog is '417 Temporary delivery error', so seems it's this '4xx' that internaly force xmail to retry ... A 5xx internal code should be the good response here for a noexisting domain name (as for the 'bad dom name syntax' problem that result in a noexisting domain name too, or dns error, generating a 4xx in place of a 5xx ...) ************************** (from email replaced with [EMAIL PROTECTED]) [PeekTime] 1141372659 : Fri, 3 Mar 2006 08:57:39 +0100 << ErrCode = -40 ErrString = Invalid server address ErrInfo = noexistingdomainname.com SMAIL SMTP-Send FF = "noexistingdomainname.com" SMTP = "mx.groupeab.com" >From = "[EMAIL PROTECTED]" To = "[EMAIL PROTECTED]" Failed ! SMTP-Error = "417 Temporary delivery error" SMTP-Server = "noexistingdomainname.com" >> [PeekTime] 1141373153 : Fri, 3 Mar 2006 09:05:53 +0100 << ErrCode = -40 ErrString = Invalid server address ErrInfo = noexistingdomainname.com SMAIL SMTP-Send FF = "noexistingdomainname.com" SMTP = "mx.groupeab.com" >From = "[EMAIL PROTECTED]" To = "[EMAIL PROTECTED]" Failed ! SMTP-Error = "417 Temporary delivery error" SMTP-Server = "noexistingdomainname.com" >> [PeekTime] 1141373667 : Fri, 3 Mar 2006 09:14:27 +0100 << ErrCode = -40 ErrString = Invalid server address ErrInfo = noexistingdomainname.com SMAIL SMTP-Send FF = "noexistingdomainname.com" SMTP = "mx.groupeab.com" >From = "[EMAIL PROTECTED]" To = "[EMAIL PROTECTED]" Failed ! SMTP-Error = "417 Temporary delivery error" SMTP-Server = "noexistingdomainname.com" >> [PeekTime] 1141374215 : Fri, 3 Mar 2006 09:23:35 +0100 << ErrCode = -40 ErrString = Invalid server address ErrInfo = noexistingdomainname.com SMAIL SMTP-Send FF = "noexistingdomainname.com" SMTP = "mx.groupeab.com" >From = "[EMAIL PROTECTED]" To = "[EMAIL PROTECTED]" Failed ! SMTP-Error = "417 Temporary delivery error" SMTP-Server = "noexistingdomainname.com" >>************************** Francis - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
