nanog mailing list archives

Re: Customer-facing ACLs


From: "Christopher Morrow" <morrowc.lists () gmail com>
Date: Mon, 10 Mar 2008 22:33:06 -0400


On Mon, Mar 10, 2008 at 7:58 PM, Ang Kah Yik <mailinglist () bangky net> wrote:

 Hi Justin (and all others on-list)

 I understand your grounds for blocking outbound SMTP for your customers
 (especially those on dynamic IP connections).
 It probably will do good to block infected customers that are spewing
 spam all over the world.

 However, considering the number of mobile workers out there who send
 email via their laptops to corporate SMTP servers, won't blocking
 outbound SMTP affect them?


vpns fix this...

 Since these corporate types (I'm guessing here) are probably unaware of
 how to change their email client's SMTP configurations, chances are that
 blocking outbound SMTP will probably cause quite a lot of pain.


uunet dialup has blocked port25 in both directions since 2002...
little to no complaints. (well, they may have received complaints
since I left, but... thank John StClair for the work behind that
filtering actually.)

 After all, there are also those who frequently move from place to place
 so they're going to have to keep changing SMTP servers every time they
 go to a new place that's on a different ISP.


many config's actually just use WCCP to transparently redirect your
smtp to an authorized SMTP server as Andy Dills points out.

-Chris


Current thread: