Date: Sat, 26 Jun 1999 16:12:47 -0400 From: "Norman C. Rice" <nrice@emu.sourcee.com> To: Chuck Robey <chuckr@picnic.mat.net> Cc: FreeBSD-ISP <FreeBSD-isp@FreeBSD.ORG> Subject: Re: sendmail relaying Message-ID: <19990626161247.A18733@emu.sourcee.com> In-Reply-To: <Pine.BSF.4.10.9906261527260.53344-100000@picnic.mat.net>; from Chuck Robey on Sat, Jun 26, 1999 at 03:32:11PM -0400 References: <Pine.BSF.4.10.9906261527260.53344-100000@picnic.mat.net>
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On Sat, Jun 26, 1999 at 03:32:11PM -0400, Chuck Robey wrote: > I thought you folks here on this list would know more than most about > sendmail, so while I'm not an ISP (not today, not on this personal > machine problem) I think this is the right audience. > > I just got a mail from ORBS (http://www.orbs.org/) telling me I'm an > open mail relay on my home machine. I run current here, no mods, and > since I thought that sendmail 8.9.3 came with relaying off by default, I > didn't need to do anything to stop it. The standard configuration file, /usr/src/sendmail/freebsd.mc, has FEATURE(relay_based_on_MX)dnl which allows relaying as follows (from sendmail's cf/README): relay_based_on_MX Turns on the ability to allow relaying based on the MX records of the host portion of an incoming recipient. See description below for more information before using this feature. ... You can also allow relaying based on the MX records of the host portion of an incoming recipient address by using FEATURE(relay_based_on_MX) For example, if your server receives a recipient of user@domain.com and domain.com lists your server in its MX records, the mail will be accepted. Note that this will stop spammers from using your host to relay spam but it will not stop outsiders from using your server as a relay for their site. -- Regards, Norman C. Rice, Jr. > I checked my machine by logging into a different one, and sending mail > to myself at a 3rd host, using my home machine (picnic.mat.net) as > relay. Worked fine, but I was expecting ahd hoping for it to fail. > > Can someone tell me what I'm missing? All the stuff I can find on > sendmail relay configuration is to carefully open up relaying (via lists > to allow or deny some users) but I think I want to deny the universe. > > Help! > > ----------------------------+----------------------------------------------- > Chuck Robey | Interests include any kind of voice or data > chuckr@picnic.mat.net | communications topic, C programming, and Unix. > 213 Lakeside Drive Apt T-1 | > Greenbelt, MD 20770 | I run picnic and jaunt, both FreeBSD-current. > (301) 220-2114 | > ----------------------------+----------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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