From owner-freebsd-questions@FreeBSD.ORG Sun Mar 24 16:14:44 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 26EFAED8 for ; Sun, 24 Mar 2013 16:14:44 +0000 (UTC) (envelope-from feenberg@nber.org) Received: from mail2.nber.org (mail2.nber.org [66.251.72.79]) by mx1.freebsd.org (Postfix) with ESMTP id CE1592A6 for ; Sun, 24 Mar 2013 16:14:43 +0000 (UTC) Received: from nber6 (nber6.nber.org [66.251.72.76]) by mail2.nber.org (8.14.4/8.14.4) with ESMTP id r2OGEZj9012632; Sun, 24 Mar 2013 12:14:36 -0400 (EDT) (envelope-from feenberg@nber.org) Date: Sun, 24 Mar 2013 12:01:11 -0400 (EDT) From: Daniel Feenberg X-X-Sender: feenberg@nber6 To: Doug Hardie Subject: Re: Client Authentication In-Reply-To: <8680FAB3-4943-4F91-935B-E11511C3FD4E@lafn.org> Message-ID: References: <8680FAB3-4943-4F91-935B-E11511C3FD4E@lafn.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Anti-Virus: Kaspersky Anti-Virus for Linux Mail Server 5.6.39/RELEASE, bases: 20130324 #9781581, check: 20130324 clean Cc: "freebsd-questions@freebsd.org List" X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 24 Mar 2013 16:14:44 -0000 On Sat, 23 Mar 2013, Doug Hardie wrote: > > On 23 March 2013, at 21:51, Mehmet Erol Sanliturk wrote: > >> >> Using Static IP in the client side , and checking Static IP of the user >> may be a possibility : In that way , any message from another IP will >> not be accepted . >> >> If this is possible for your systems , it may be checked for usability >> . >> >> One difficulty is that each user should obtain a Static IP and can not >> connect to his/her ISP from another IP . >> >> Good side is that nobody can connect to ISP of the user from another IP >> : It supplies hardware security ( we are assuming that the user >> computer is not captured ) .. > > That is an interesting idea, but unfortunately our users tend to travel > a lot and need to be able to access mail from anywhere. Also, static > IPs can get quite expensive from some ISPs. Our users are pretty much > on fixed incomes and any expense is a hardship for them. Can you filter outgoing mail with Spamassassin? How about refusing to relay mail from addresses in a good DNSBL? Do you rate-limit outgoing mail? Can you just refuse to relay mail from other continents, using a geolocation service? daniel feenberg > > -- Doug > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" >