From owner-freebsd-questions Thu Dec 30 13:58:31 1999 Delivered-To: freebsd-questions@freebsd.org Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by hub.freebsd.org (Postfix) with ESMTP id 2264914C1A for ; Thu, 30 Dec 1999 13:58:29 -0800 (PST) (envelope-from mw@theatre.sax.de) Received: (from uucp@localhost) by sax.sax.de (8.9.3/8.9.3) with UUCP id WAA28498; Thu, 30 Dec 1999 22:58:12 +0100 (CET) Received: by theatre.sax.de (8.9.3/8.6.12-s1) id WAA63576; Thu, 30 Dec 1999 22:55:34 +0100 (CET) Date: Thu, 30 Dec 1999 22:55:34 +0100 From: Martin Welk To: Sheldon Hearn Cc: John , Jim Conner , freebsd-questions@FreeBSD.ORG Subject: Re: Wrapping Sendmail [was: Re: DNS Setup] Message-ID: <19991230225533.C63036@theatre.sax.de> References: <4.1.19991219141354.00957160@mail.udel.edu> <86563.945689682@axl.noc.iafrica.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <86563.945689682@axl.noc.iafrica.com>; from sheldonh@uunet.co.za on Mon, Dec 20, 1999 at 01:34:42PM +0200 Organization: Private UUCP/Usenet site. X-Operating-System: FreeBSD http://www.freebsd.org/ Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Mon, Dec 20, 1999 at 01:34:42PM +0200, Sheldon Hearn wrote: > Using TCP Wrappers for sendmail is only really useful for special cases, > for example for relay-only hosts that don't accept incoming connections, > or hosts that only accept incoming connections from a limited number of > mail gateways. IP based mail filtering is in the most scenarios only a solution for the worst case, constant attacks or tries on your mailer daemon or denial of service attacks. Instead, you should read the sendmail documentation for prevention against misusing your mailer and filtering e-mail. First of all, don't permit relaying for domains and/or hosts you don't to relay for. This is the default for sendmail starting with version 8.9.x and it checks the DNS MX records if your host is a valid MX for a domain and decided by this, if it takes the mail or not. You can also include several black lists into sendmail from projects that collect data about repeating SPAM from hosts so you can at least include well-known spammer sites to block them from yours. We did so at a private ISP I do administration work for, and it reduced our non-wanted crap to almost nothing. Regards, Martin -- /| /| | /| / ,,You know, there's a lot of opportunities, / |/ | artin |/ |/ elk if you're knowing to take them, you know, there's a lot of opportunities, Freiberg/Saxony, Germany if there aren't you can make them, mw@sax.de / mw@theatre.sax.de make or break them!'' (Tennant/Lowe) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message