Re: How to block senders whose domain without a MX record
Am 16.02.2012 14:06, schrieb daniel zhou: Hi Group, The document segment about the reject_unknown_sender_domain says that it will reject the domain without A record or MX record. Does it mean that only domains with both A and MX record will be accepted? Or, it means any domains with only A record,domains with only MX record or with both will be accepted. Can anyone clarify it? Thanks! both missing I just want to block the senders whose domain without MX record, even if it has an A record. you must not do this because you will block normal mail without any reason! i was there by verify importing newsletter-lists with a php-application and had to change this because well known contacts of our customers were thrown out while they had active mail in both directions on the normal server signature.asc Description: OpenPGP digital signature
RE: How to block senders whose domain without a MX record
Hi, It is only applicable to the domains that are not known, ie no DNS Resolution. So based on your request, it could accept all the domain that have a DNS, even if they dont have an MX record. Franck --- De : owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org] De la part de daniel zhou Envoyé : jeudi 16 février 2012 14:06 À : postfix-users@postfix.org Objet : How to block senders whose domain without a MX record Hi Group, The document segment about the reject_unknown_sender_domain says that it will reject the domain without A record or MX record. Does it mean that only domains with both A and MX record will be accepted? Or, it means any domains with only A record,domains with only MX record or with both will be accepted. Can anyone clarify it? Thanks! I just want to block the senders whose domain without MX record, even if it has an A record. Thanks! Daniel Zhou
Re: How to block senders whose domain without a MX record
On Thu, Feb 16, 2012 at 05:06:22AM -0800, daniel zhou wrote: The document segment about the reject_unknown_sender_domain says that it will reject the domain without A record or MX record. Does it mean that only domains with both A and MX record will be accepted? Or, it means any domains with only A record,domains with only MX record or with both will be accepted. Can anyone clarify it? Thanks! An unknown sender domain means that the name did not resolve in a way such that mail could be delivered to it. An A record, even if it's 0.0.0.0 or 127.x.x.x or any other address that might not be deliverable for some reason, qualifies as a known sender domain. Unless of course there is a MX, and that name does not resolve: then it is unknown. Also a malformed MX record is unknown. IIRC these rules can be found in RFC 5321 and predecessors. I just want to block the senders whose domain without MX record, even if it has an A record. There is check_sender_mx_access, but I don't know if it strictly works the way you want. Also, I don't think your idea is a good one. You will block some real mail, I bet, while making little if any impact on spam. -- http://rob0.nodns4.us/ -- system administration and consulting Offlist GMX mail is seen only if /dev/rob0 is in the Subject:
Re: How to block senders whose domain without a MX record
Thanks all for the clarification. You are right. That idea may block more real mail than the spam ones. From: /dev/rob0 r...@gmx.co.uk To: postfix-users@postfix.org Sent: Thursday, February 16, 2012 9:28 PM Subject: Re: How to block senders whose domain without a MX record On Thu, Feb 16, 2012 at 05:06:22AM -0800, daniel zhou wrote: The document segment about the reject_unknown_sender_domain says that it will reject the domain without A record or MX record. Does it mean that only domains with both A and MX record will be accepted? Or, it means any domains with only A record,domains with only MX record or with both will be accepted. Can anyone clarify it? Thanks! An unknown sender domain means that the name did not resolve in a way such that mail could be delivered to it. An A record, even if it's 0.0.0.0 or 127.x.x.x or any other address that might not be deliverable for some reason, qualifies as a known sender domain. Unless of course there is a MX, and that name does not resolve: then it is unknown. Also a malformed MX record is unknown. IIRC these rules can be found in RFC 5321 and predecessors. I just want to block the senders whose domain without MX record, even if it has an A record. There is check_sender_mx_access, but I don't know if it strictly works the way you want. Also, I don't think your idea is a good one. You will block some real mail, I bet, while making little if any impact on spam. -- http://rob0.nodns4.us/ -- system administration and consulting Offlist GMX mail is seen only if /dev/rob0 is in the Subject:
