Date: Fri, 22 Jul 2011 10:32:17 +0200 From: Polytropon <freebsd@edvax.de> To: Robert Huff <roberthuff@rcn.com> Cc: ssgriffonuser <ssgriffonuser@gmail.com>, freebsd-questions@freebsd.org Subject: Re: Sendmail not accepting connections on port 25 Message-ID: <20110722103217.8daa47a1.freebsd@edvax.de> In-Reply-To: <20008.57778.393668.758638@jerusalem.litteratus.org> References: <201107191631.p6JGVu6V034273@mail.r-bonomi.com> <4E26589B.9070406@gmail.com> <4E27E3CA.4080803@bananmonarki.se> <4E2878EB.7060502@gmail.com> <20008.57778.393668.758638@jerusalem.litteratus.org>
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On Thu, 21 Jul 2011 22:34:26 -0400, Robert Huff wrote: > > ssgriffonuser writes: > > > > My isp is blocking outgoing traffic on port 25. > > > > Yeah, it looks like your right. I never would've considered my ISP > > blocking outbound traffic from my home, but I suppose it makes > > sense. Does _not_ make sense as it just hides symptoms, but does not cure the initial problem. > It is my understanding many I.S.P.s in the U,S, do, as part of > spam control procedures. I am obliged to relay through my I.S.P.; > after some initial set-up issues, this works flawlessly as long as > at least one relay machine is up. Same here - but different. Due to the fact that more than 90% of world's mail traffic is spam, many providers of mail services have the policy to _not_ accept mail coming from a "suspicious" IP. This is mostly ranges of dynamic IPs assigned to "dial-up" (home consumer) services, but may also contain other "blacklisted" IPs. In conclusion, you often have the situation that you can actually _send_ a message, but the target ISP's mail server will deny to accept it. The same way of "manipulating the symptoms", I relay my mail through my ISP's MX. Thanks to sendmail's SmartHost setting, this is easy once set up. In the mail logs, you can then see when messages are commited to the MX (you do _not_ see delivery status to target anymore). Blocking _outgoing_ "mail traffic" is also an interesting approach, so my initial guess "check if ISP is blocking something" was right... :-) The initial problem, the "creation" of spam, is mainly due to hijacked "Windows" PCs (and servers) in homes and offices (the larger the "better"). Most people who run an own mailserver, and even if it's just for outgoing mail, do this in a _proper_ way. Sadly, those have to suffer from the carelessness of the masses. Business as usual. -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
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