Re: How to disable email drlivery on A record
Le 08/04/2011 13:52, Reindl Harald a écrit : Am 08.04.2011 13:48, schrieb Gábor Lénárt: On Fri, Apr 08, 2011 at 05:05:45PM +0530, kshitij mali wrote: HI All Postfix will try to deliver email based on A record suppose the mx record is missing , so how to diable this . I mean to say postfix should send email based on MX record only and if mx record not bound then immediatly bounce the sender . I don't think it's a good idea, it's part of the standard. We have smaller (legitime) mail servers receiving mails having only A record. Why would I need MX record, if A is ok for me? I only set up MX records when it's needed (the DNS name itself has an A record already but MTA receiving its mail is not at the same address as A record would tell), otherwise I leave it alone with the A record only. I think there is no problem with this practice. in fact you should not do this because it needs two dns-queries for the sending server everytime and you set the MX only once I see no difference: - with no MX: 1- lookup MX: none 2- lookup A for domain - with MX: 1- lookup MX: returns say host.example.com 2- lookup A for host.example.com but yes, it is in the standard and postfix will hopefully not support such broken setup
Re: How to disable email drlivery on A record
mouss: - with MX: 1- lookup MX: returns say host.example.com Typically, the result also contains an additional information section with the A records, and perhaps some name server records. These will be cached by the local DNS server, subject to sanity checks. 2- lookup A for host.example.com Which will already be cached by the local DNS server. Wietse
Re: How to disable email drlivery on A record
Am 16.04.2011 23:54, schrieb mouss: in fact you should not do this because it needs two dns-queries for the sending server everytime and you set the MX only once I see no difference: - with no MX: 1- lookup MX: none 2- lookup A for domain - with MX: 1- lookup MX: returns say host.example.com 2- lookup A for host.example.com on the first look but in reality one mailserver is hosting many domains if any nameserver has our barracuda.theounge.net in his cache he can answer the MX for 200 other domains from his cache would the 200 domains have no MX record the first query would have no result and then the nameserver needs a second one for the a-record which has to be cached for each domain even if it would be the same ip-address additionally: negative dns-hits have a small TTL positive hits usually have a ttl from 1 hour to two days so there is a hughe difference in the background signature.asc Description: OpenPGP digital signature
Re: How to disable email drlivery on A record
* kshitij mali foreplay...@gmail.com: HI All Postfix will try to deliver email based on A record suppose the mx record is missing , so how to diable this. You can't. It's part of the standard. I mean to say postfix should send email based on MX record only and if mx record not bound then immediatly bounce the sender . I use transport_maps for that: holtmail.comerror:5.1.2 You meant hotmail.com, not holtmail.com hotmial.com error:5.1.2 You meant hotmail.com, not hotmial.com hotmail.co error:5.1.2 You meant hotmail.com, not hotmail.co hotmal.com error:5.1.2 You meant hotmail.com, not hotmal.com hormail.com error:5.1.2 You meant hotmail.com, not hormail.com hotmil.com error:5.1.2 You meant hotmail.com, not hotmil.com hotrmail.comerror:5.1.2 You meant hotmail.com, not hotrmail.com hotnail.com error:5.1.2 You meant hotmail.com, not hotnail.com holmail.com error:5.1.2 You meant hotmail.com, not holmail.com hotmsil.com error:5.1.2 You meant hotmail.com, not hotmsil.com hotmali.com error:5.1.2 You meant hotmail.com, not hotmali.com hotmaile.de error:5.1.2 You meant hotmail.de, not hotmaile.de hotmain.com error:5.1.2 You meant hotmail.com, not hotmain.com otmail.com error:5.1.2 You meant hotmail.com, not otmail.com hotamil.com error:5.1.2 You meant hotmail.com, not hotamil.com hotmaill.comerror:5.1.2 You meant hotmail.com, not hotmaill.com homail.com error:5.1.2 You meant hotmail.com, not homail.com hpotmail.de error:5.1.2 You meant hotmail.com, not hpotmail.de -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
Re: How to disable email drlivery on A record
Am 08.04.2011 13:35, schrieb kshitij mali: HI All Postfix will try to deliver email based on A record suppose the mx record is missing , so how to diable this . I mean to say postfix should send email based on MX record only and if mx record not bound then immediatly bounce the sender why do you want to make your server unrelieable? there are enough domains out there which have only a a-record and a well working MTA on this address, what you trie to do reslts in bouncing for valid addresses signature.asc Description: OpenPGP digital signature
Re: How to disable email drlivery on A record
On Fri, Apr 08, 2011 at 05:05:45PM +0530, kshitij mali wrote: HI All Postfix will try to deliver email based on A record suppose the mx record is missing , so how to diable this . I mean to say postfix should send email based on MX record only and if mx record not bound then immediatly bounce the sender . I don't think it's a good idea, it's part of the standard. We have smaller (legitime) mail servers receiving mails having only A record. Why would I need MX record, if A is ok for me? I only set up MX records when it's needed (the DNS name itself has an A record already but MTA receiving its mail is not at the same address as A record would tell), otherwise I leave it alone with the A record only. I think there is no problem with this practice. - Gábor
Re: How to disable email drlivery on A record
Am 08.04.2011 13:48, schrieb Gábor Lénárt: On Fri, Apr 08, 2011 at 05:05:45PM +0530, kshitij mali wrote: HI All Postfix will try to deliver email based on A record suppose the mx record is missing , so how to diable this . I mean to say postfix should send email based on MX record only and if mx record not bound then immediatly bounce the sender . I don't think it's a good idea, it's part of the standard. We have smaller (legitime) mail servers receiving mails having only A record. Why would I need MX record, if A is ok for me? I only set up MX records when it's needed (the DNS name itself has an A record already but MTA receiving its mail is not at the same address as A record would tell), otherwise I leave it alone with the A record only. I think there is no problem with this practice. in fact you should not do this because it needs two dns-queries for the sending server everytime and you set the MX only once but yes, it is in the standard and postfix will hopefully not support such broken setup signature.asc Description: OpenPGP digital signature
Re: How to disable email drlivery on A record
On Fri, Apr 08, 2011 at 01:52:29PM +0200, Reindl Harald wrote: I don't think it's a good idea, it's part of the standard. We have smaller (legitime) mail servers receiving mails having only A record. Why would I need MX record, if A is ok for me? I only set up MX records when it's needed (the DNS name itself has an A record already but MTA receiving its mail is not at the same address as A record would tell), otherwise I leave it alone with the A record only. I think there is no problem with this practice. in fact you should not do this because it needs two dns-queries for the sending server everytime and you set the MX only once Yes that's true, however we have some customers with really low-traffic mail domains but they have totally messed up DNS setup sometimes (having IP address in MX record, CNAME/MX collusion etc - and we have no control over their zones) so only in this case it's a local policy here to suggest the simpliest dns setup, even if it needs an MX lookup first then for A. I would not do this with any other MTAs receiving more mails than only some.
Re: How to disable email drlivery on A record
kshitij mali: HI All Postfix will try to deliver email based on A record suppose the mx record is missing , so how to diable this . This behavior is required by the Internet SMTP standard. This is not configurable. Wietse
