RE: Mail Routing Question
Good catch. I was trying to be succinct, but didn't realize that one couldn't use an IP rather than the hostname. So the corrected example should be something like this then: mailIN A 192.168.0.2 aaa IN A 192.168.1.1 IN MX 10 mail.aaa.com. ...Kevin -- Kevin Miller Network/email Administrator, CBJ MIS Dept. 155 South Seward Street Juneau, Alaska 99801 Phone: (907) 586-0242, Fax: (907) 586-4588 Registered Linux User No: 307357 -Original Message- From: owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org] On Behalf Of /dev/rob0 Sent: Thursday, November 16, 2017 5:57 PM To: postfix-users@postfix.org Subject: Re: Mail Routing Question On Thu, Nov 16, 2017 at 10:43:16PM +, Kevin Miller wrote: > You can point the A record for aaa.com to one IP and the MX record for > it to another. Yes, but not as per your example. > I.e. > aaa IN A 192.168.1.1 > IN MX 10 192.168.1.2 The RDATA for MX is "integer hostname". In your example the "192.168.1.2" would be read as a hostname, and noting the lack of trailing dot, the zone file's current $ORIGIN value would be appended. > In the example above, a web page to http://aaa.com would go to > 192.168.1.1, whereas an SMTP server would connect to 192.168.1.2. In this example mail would most likely not be deliverable. The MX record in DNS would point to a name which probably does not exist. -- http://rob0.nodns4.us/ Offlist GMX mail is seen only if "/dev/rob0" is in the Subject:
Re: Mail Routing Question
On Thu, Nov 16, 2017 at 10:43:16PM +, Kevin Miller wrote: > You can point the A record for aaa.com to one IP and the MX record > for it to another. Yes, but not as per your example. > I.e. > aaa IN A 192.168.1.1 > IN MX 10 192.168.1.2 The RDATA for MX is "integer hostname". In your example the "192.168.1.2" would be read as a hostname, and noting the lack of trailing dot, the zone file's current $ORIGIN value would be appended. > In the example above, a web page to http://aaa.com would go to > 192.168.1.1, whereas an SMTP server would connect to 192.168.1.2. In this example mail would most likely not be deliverable. The MX record in DNS would point to a name which probably does not exist. -- http://rob0.nodns4.us/ Offlist GMX mail is seen only if "/dev/rob0" is in the Subject:
Re: Mail Routing Question
> On 16 November 2017, at 14:45, Viktor Dukhovni > wrote: > > > >> On Nov 16, 2017, at 5:32 PM, Doug Hardie wrote: >> >> I have a domain, say: aaa.com for which I receive mail. Currently I have A >> records in DNS for aaa.com and mail.aaa.com as well as a MX record for >> aaa.com. All three of them point to the same IP address which is where >> postfix is running. There is a political issue with the A record for >> aaa.com and it "needs" to be changed to elsewhere. I somehow seem to recall >> that there are some MTAs that do not use the MX records, but only check the >> A records. > > Any MTA that fails to check MX records is badly broken, and can barely > deliver email to any domains that matter (all the big players have > MX hosts separate from their A/ records used primarily for HTTP). > >> Will changing the A record for aaa.com cause the loss of some incoming mail > > No. > > -- > Viktor. > Thanks to all. I have changed the A record.
Re: Mail Routing Question
Doug Hardie skrev den 2017-11-16 23:32: Will changing the A record for aaa.com cause the loss of some incoming mail? no, if that changed ip accept delivery of that recipient domain back to what mx does ?, it only defines a seperate hostname to deliver mail to if mail and other servicefs on hostnamea is not same as service on hostnameb eq if you only have single ip, do not use mx setup people are misguided if that say mx is needed to recieve emails, i have seen fool bounces that i need mx to recieve bounces, where the bounced text was rejected mail from me since i did inded not have a mx, i dont need a complex world setup for a single ip
Re: Mail Routing Question
> On Nov 16, 2017, at 5:32 PM, Doug Hardie wrote: > > I have a domain, say: aaa.com for which I receive mail. Currently I have A > records in DNS for aaa.com and mail.aaa.com as well as a MX record for > aaa.com. All three of them point to the same IP address which is where > postfix is running. There is a political issue with the A record for aaa.com > and it "needs" to be changed to elsewhere. I somehow seem to recall that > there are some MTAs that do not use the MX records, but only check the A > records. Any MTA that fails to check MX records is badly broken, and can barely deliver email to any domains that matter (all the big players have MX hosts separate from their A/ records used primarily for HTTP). > Will changing the A record for aaa.com cause the loss of some incoming mail No. -- Viktor.
RE: Mail Routing Question
You can point the A record for aaa.com to one IP and the MX record for it to another. I.e. aaa IN A 192.168.1.1 IN MX 10 192.168.1.2 All the MX record does is tell the world what mail host to use for a given domain. So you may have a web server running on aaa.com but not your email server. When someone queries aaa.com the A record is normally returned, but if the type is set to MX then the MX record is returned instead. In the example above, a web page to http://aaa.com would go to 192.168.1.1, whereas an SMTP server would connect to 192.168.1.2. Be sure that you update the PTR records for the hosts when you change them... ...Kevin -- Kevin Miller Network/email Administrator, CBJ MIS Dept. 155 South Seward Street Juneau, Alaska 99801 Phone: (907) 586-0242, Fax: (907) 586-4588 Registered Linux User No: 307357 -Original Message- From: owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org] On Behalf Of Doug Hardie Sent: Thursday, November 16, 2017 1:32 PM To: Postfix users Subject: Mail Routing Question I have a domain, say: aaa.com for which I receive mail. Currently I have A records in DNS for aaa.com and mail.aaa.com as well as a MX record for aaa.com. All three of them point to the same IP address which is where postfix is running. There is a political issue with the A record for aaa.com and it "needs" to be changed to elsewhere. I somehow seem to recall that there are some MTAs that do not use the MX records, but only check the A records. Will changing the A record for aaa.com cause the loss of some incoming mail? -- Doug
Mail Routing Question
I have a domain, say: aaa.com for which I receive mail. Currently I have A records in DNS for aaa.com and mail.aaa.com as well as a MX record for aaa.com. All three of them point to the same IP address which is where postfix is running. There is a political issue with the A record for aaa.com and it "needs" to be changed to elsewhere. I somehow seem to recall that there are some MTAs that do not use the MX records, but only check the A records. Will changing the A record for aaa.com cause the loss of some incoming mail? -- Doug