Subject: Re: [Asrg] article: port 25 blocking

From: Danny Angus <[email-masked]>
Date: Tue, 12 Apr 2005 08:57:59 +0100

> Those who legitimately use outbound port 25 access
> have alternatives already which include
<snip/>
> asking your ISP for an exemption

If ISP's blocked port 25 and provided policed exemptions it would introduce
weak trust into an area where there is conspicuously no trust at all.

I don't see this as any more contentious than the blacklisting of ISP's
DHCP IP blocks, which stung some people at first but protected a whole lot
more in the long run.

d.

***************************************************************************
The information in this e-mail is confidential and for use by the addressee(s) only. If you are not the intended recipient (or responsible for delivery of the message to the intended recipient) please notify us immediately on 0141 306 2050 and delete the message from your computer. You may not copy or forward it or use or disclose its contents to any other person. As Internet communications are capable of data corruption Student Loans Company Limited does not accept any  responsibility for changes made to this message after it was sent. For this reason it may be inappropriate to rely on advice or opinions contained in an e-mail without obtaining written confirmation of it. Neither Student Loans Company Limited or the sender accepts any liability or responsibility for viruses as it is your responsibility to scan attachments (if any). Opinions and views expressed in this e-mail are those of the sender and may not reflect the opinions and views of The Student Loans Company Limi!
 ted.

This footnote also confirms that this email message has been swept for the presence of computer viruses.

**************************************************************************

_______________________________________________
Asrg mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/asrg

---

From: Daniel Feenberg <[email-masked]>
Date: Tue, 12 Apr 2005 07:39:22 -0400 (EDT)

> DHCP IP blocks, which stung some people at first but protected a whole lot

Can you suggest a DNSBL that does this? We are using MAPS and Spamhaus,
but MAPS only lists a block if the ISP owning the block specifically
requests it, and Spamhaus seems to be very weak in this area also. For
example, we get several hundred messages from east.verizon.net every
day. Could there actually be legitimate MTAs in that block? 

An advantage of using DNSBLs for blocking port 25 rather than having the
ISP do it at the router is that it is what economists call "incentive
compatible". That is, the work and expense (such as they are) are borne
by the individual/organization that benefits most. The benefit to the
source ISP is mostly a reduction in abuse mail - which many ISPs seem to
ignore anyway. The benefit to the receiving ISP is a reduction in inbound
spam, which is a big incentive. 

Daniel Feenberg

> The information in this e-mail is confidential and for use by the addressee(s) only. If you are not the intended recipient (or responsible for delivery of the message to the intended recipient) please notify us immediately on 0141 306 2050 and delete the message from your computer. You may not copy or forward it or use or disclose its contents to any other person. As Internet communications are capable of data corruption Student Loans Company Limited does not accept any  responsibility for changes made to this message after it was sent. For this reason it may be inappropriate to rely on advice or opinions contained in an e-mail without obtaining written confirmation of it. Neither Student Loans Company Limited or the sender accepts any liability or responsibility for viruses as it is your responsibility to scan attachments (if any). Opinions and views expressed in this e-mail are those of the sender and may not reflect the opinions and views of The Student Loans Company Li!
mi!