Security Basics mailing list archives
RE: RBLs for SPAM Control
From: "David Gillett" <gillettdavid () fhda edu>
Date: Mon, 8 Aug 2005 09:05:01 -0700
More and more providers of dynamic IP addresses (i.e., ISPs) are blocking them as SMTP sources, and requiring DHCP users to relay via a server provided by the ISP. So "direct to MX" traffic from DHCP clients should only come from viruses and spambots, which don't know about the relay requirement. Done right, this isn't nearly the problem that many half- knowledgeable users expect it to be. MOST ISPs recognize that their customers need to be able to send email with From: headers referring to personal or employer domains, and so don't ALSO try to filter on From: domain for properly-relayed traffic. A very few ISPs need to converse with the business end of a clue-by-four to understand this; once they do, legitimate email flows smoothly and cleanly. David Gillett
-----Original Message----- From: Alexis [mailto:bonobo () bigpond net au] Sent: Thursday, August 04, 2005 8:48 AM To: security-basics () securityfocus com Subject: Re: RBLs for SPAM Control On Thu, 4 Aug 2005 02:12 pm, you wrote:As a rule of thumb, most RBLS automatically list dynamicIPs used for dialups / modem pools of ISPs as suspicious. Simply because anymail from adynamic IP is considered unsafe, in RBL terms !Interesting . . . . i wonder how many false-positives this creates? i would think it would be quite a few, given the number of people who send emails from dynamic IPs . . . .Nothing much you can do, other than ask your ISP to 1) addreverse DNS forthe IP blocks and 2) try to get the IP block removed fromthe list(s) *nod* Okay, thanks. Alexis.
Current thread:
- Re: RBLs for SPAM Control security (Aug 01)
- <Possible follow-ups>
- RE: RBLs for SPAM Control Chris Santerre (Aug 02)
- Re: RBLs for SPAM Control Devdas Bhagat (Aug 02)
- Re: RBLs for SPAM Control Micheal Espinola Jr (Aug 02)
- Re: Re: RBLs for SPAM Control Phil Cryer (Aug 03)
- Re: RBLs for SPAM Control Alexis (Aug 03)
- Re: RBLs for SPAM Control Devdas Bhagat (Aug 04)
- Re: RBLs for SPAM Control Alexis (Aug 05)
- Message not available
- Re: RBLs for SPAM Control Alexis (Aug 05)
- Re: RBLs for SPAM Control Devdas Bhagat (Aug 08)
- RE: RBLs for SPAM Control David Gillett (Aug 10)
- Re: RBLs for SPAM Control Devdas Bhagat (Aug 04)
- Re: RBLs for SPAM Control maxfield (Aug 08)