--On 27 December 2006 10:25:20 +0100 Renaud Allard <[EMAIL PROTECTED]> wrote:
> > > Craig Whitmore wrote: >>>> I would like to increase a spam defense of our server by checking if a >>>> sender really represents an MX server of his/her organization. So if a >>>> certain PC is trying to send me an e-mail from [EMAIL PROTECTED] then we >>>> will check if this person's IP address is within MX servers of >>>> domain.com, otherwise we'll refuse to accept the mail. >>>> >>>> Is it feasible? How can I achieve this? >>>> >> >> If a domain has set up SPF or SenderID records then you can use those so >> make sure the emails are coming from the correct places. >> > > > Unfortunately, many sites who have implemented SPF have implemented them > incorrectly. > Here is a very good example: > /var/log/exim4/rejectlog.13.gz:2006-12-14 15:51:53 H=host60.citrix.com > (FTLPEXCHSMTP01.citrite.net) [66.165.176.60] > F=<[EMAIL PROTECTED]> rejected RCPT <[EMAIL PROTECTED]>: SPF > check failed. > > If you strictly check SPF, you will reject good mails because many sites > administrators just forget they have servers sending mails from web > interfaces or in an automated way. Rejecting their emails should be an efficient way of concentrating their minds on fixing the problem. -- Ian Eiloart IT Services, University of Sussex -- ## List details at http://www.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://www.exim.org/eximwiki/
