Security Basics mailing list archives
Re: Sendmail 8.11 configuration/security issue
From: "simsjs" <sims () interex org>
Date: Fri, 03 Jan 2003 09:50:23 -0800
Although I haven't written a rule to do this, you should be able to use procmail to create a rule for this. You could check the "From:" line and if it matches yourdomain.com then check the "Received: from" to make sure that is your smtp server. If it is not then filter it, move it, modify it, or whatever you want. Hopefully you get some ideas from this. Jeff *********** REPLY SEPARATOR *********** On 1/3/2003 at 4:38 PM oobs3c02 () attbi com wrote:
I'm running sendmail 8.11 on a Solaris server. The server has a single interface and sits in my DMZ. I'm trying to find a way to block inbound mail with my domain spoofed as the sender. The scenario turned up when a person I know received spam with the sender being spoofed showing amber () mydomain com and recipient being myfriend () mydomain com. After inspecting the mail headers, we discovered that the source IP was definitely external. We've scoured sendmail.org, arachnoid.com, cauce.org and all the books we have and could not find this scenario speifically mentioned. Problems/Questions 1. If we block spammers by domain as recommended at http://www.arachnoid.com/lutusp/antispam.html#filter_forwarding, how do we get around our internal users being blocked from sending mail out? 2. Does anyone know of a way to check the network that a specific domain is sending from? This way we could look at mydomain.com and compare it to a specific subnet that we allow. Thanks in advance for your help. Jim
Current thread:
- Sendmail 8.11 configuration/security issue oobs3c02 (Jan 03)
- Re: Sendmail 8.11 configuration/security issue simsjs (Jan 03)
- Re: Sendmail 8.11 configuration/security issue john65 (Jan 03)
- Re: Sendmail 8.11 configuration/security issue Don Voss (Jan 05)
- Re: Sendmail 8.11 configuration/security issue Timothy M. Lyons (Jan 06)
- <Possible follow-ups>
- RE: Sendmail 8.11 configuration/security issue Keith T. Morgan (Jan 03)
- Re: Sendmail 8.11 configuration/security issue Ned Fleming (Jan 03)
- Re: Sendmail 8.11 configuration/security issue Wahyu Kelik (Jan 05)
- RE: Sendmail 8.11 configuration/security issue john65 (Jan 05)
- Re: Sendmail 8.11 configuration/security issue Ned Fleming (Jan 03)