From owner-freebsd-questions Thu Mar 7 3:12:53 2002 Delivered-To: freebsd-questions@freebsd.org Received: from 217-126-145-95.uc.nombres.ttd.es (217-126-145-95.uc.nombres.ttd.es [217.126.145.95]) by hub.freebsd.org (Postfix) with ESMTP id D281E37B4A0 for ; Thu, 7 Mar 2002 03:12:35 -0800 (PST) Received: by unicorn.ea4els.ampr.org (Postfix, from userid 1001) id E7B453165; Thu, 7 Mar 2002 12:12:32 +0100 (CET) To: freebsd-questions@freebsd.org Subject: Re: sendmail and dns References: <0B0368CED76DD4118E1200D0B73E9B5D041E9F20@MAIL1> From: Simon J Mudd Date: 07 Mar 2002 12:12:32 +0100 In-Reply-To: <0B0368CED76DD4118E1200D0B73E9B5D041E9F20@MAIL1> Message-ID: <86g03cljhb.fsf@unicorn.ea4els.ampr.org> Lines: 50 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Dewhirst.M@UCLES.org.uk (Mike Dewhirst) writes: > Sometimes my box (4.4) can't send mails because the relay server it connects > to can't reverse look it up. > > As in: > > I have a domain called mydomain.com. > I have a box called mybox.mydomain.com. > I have a A record in my ISP's zone file for mybox.mydomain.com > I can not resolve mybox.mydomain.com to an ip. > > Should mybox.mydomain.com be a CNAME record? No. Sendmail is probably doing a reverse lookup from your ip address to find out your name. This is what normally goes in the logs. So if you box is called mybox.mydomain.com and has an A record 1.2.3.4 Then the DNS should have two records, ideally: mybox.mydomain.com IN A 1.2.3.4 4.3.2.1.in-addr.arpa. IN PTR mybox.mydomain.com. The ptr record may show something different and it is probably this which is wrong. If you want to check the forward record do: dig @ns.of.provider A mybox.mydomain.com dig @ns.of.provider PTR 4.3.2.1.in-addra.arpa. If that works, but it fails when you remove the @ns.of.provider then they have setup the DNS locally correctly but globally the information is not being propogated to the rest of the Internet. However it sounds like a local issue which may fail globally too. I think that sendmail if it can't resolve the name from the ip address shouldn't fail. Perhaps you have some sort of tcp timeout which is being triggered "during the wait"? Without real names, addresses, logs and configuration files it's pretty hard to know. Simon -- Simon J Mudd, Tel: +34-91-408 4878, Mobile: +34-605-085 219 Madrid, Spain. email: sjmudd@pobox.com, Postfix RPM Packager To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message