Security Basics mailing list archives
RE: email address "spoofed"
From: "Aditya, ALD [Aditya Lalit Deshmukh]" <aditya.deshmukh () online gateway technolabs net>
Date: Sat, 13 Mar 2004 10:25:19 +0530
A great many ISPs who hand out addresses via DHCP maintain a set of generic reverse-DNS entries for their scopes. On the one hand, this greatly diminishes the value of this lookup as an anti-spam measure; on the other hand, it avoids the particular problem you describe.
the problem is that my address when forward resolved is different from reverse resolution.
A more effective measure employed by several ISPs is to block outbound SMTP at their borders, except for their own officially sanctioned email server(s). This cuts the propagation of viruses with their own SMTP engine, and use of spam-sending packages with their own, to virtually nil, and if they don't turn on the reverse check, they can probably (*safely*) avoid setting up reverse records for their DHCP scopes.
this would work only if the isp allowed any and every email from any domain to pass through, that is why i run myy own mail server with the A and MX recored pointing to my smtp server address
If your ISP allows arbitrary port 25 traffic to the world, but won't set up reverse ranges on its DNS servers, maybe you should evaluate some of their competitors....
ther competitors are worse, atleast this one has a very responcive help desk and good people at the phone and not some script monkeys, one call is what it takes to resolve any complicated matter. -aditya ________________________________________________________________________ Delivered using the Free Personal Edition of Mailtraq (www.mailtraq.com) --------------------------------------------------------------------------- Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off any course! All of our class sizes are guaranteed to be 10 students or less to facilitate one-on-one interaction with one of our expert instructors. Attend a course taught by an expert instructor with years of in-the-field pen testing experience in our state of the art hacking lab. Master the skills of an Ethical Hacker to better assess the security of your organization. Visit us at: http://www.infosecinstitute.com/courses/ethical_hacking_training.html ----------------------------------------------------------------------------
Current thread:
- email address "spoofed" Tim Laureska (Mar 08)
- RE: email address "spoofed" David Gillett (Mar 08)
- RE: email address "spoofed" Aditya, ALD [Aditya Lalit Deshmukh] (Mar 10)
- RE: email address "spoofed" David Gillett (Mar 11)
- RE: email address "spoofed" Aditya, ALD [Aditya Lalit Deshmukh] (Mar 15)
- RE: email address "spoofed" David Gillett (Mar 15)
- RE: email address "spoofed" Aditya, ALD [Aditya Lalit Deshmukh] (Mar 10)
- RE: email address "spoofed" David Gillett (Mar 08)
- Re: email address "spoofed" Adrian Hall (Mar 11)
- <Possible follow-ups>
- RE: email address "spoofed" Chinnery, Paul (Mar 08)
- Re: email address "spoofed" Sean Earp (Mar 08)
- Re: email address "spoofed" Webb Wang CS (Mar 08)