Toby DiPasquale on 11 Apr 2007 21:33:28 -0000

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: [PLUG] What is the best way to create a tunnel or a forward?iptables?

On Wed, Apr 11, 2007 at 05:16:55PM -0400, Brian Stempin wrote:
> When they send e-mail, their client contacts your server at your location
> on port 25?  No ISP should be blocking that because anybody using an
> external mail service would need port 25.  I send mail out to 3 different
> servers on port 25, depending on which account I'm using.
> That's not always true.  Some ISPs (Verizon, for instance) force you to use
> their relay servers in an attempt to cut down on spam.  I've had many
> customers complain because of this.  It makes setting up simple email
> accounts a pain in the arse.

Further, T-Mobile and iBahn (both nationwide wireless providers) proxy or
block outbound port 25 in order to reduce spam. T-Mobile is extremely
annoying in this regard, as it redirects your outgoing SMTP session into
its sendmail proxy but then doesn't support SMTP AUTH. What this means is
that if you use SMTP AUTH and want to send mail from a Starbucks, Borders
or pretty much any airport in the U.S., you're screwed.

iBahn redirects you to a proxy that doesn't work at all. It actually returns a 
550 for valid commands. So, in those cases, if your ISP doesn't support the 
alternate submission port (587), then you cannot send mail from those carriers. 

This is fresh in my mind, just coming back from S.F. where I was subjected to 
both T-Mobile and iBahn and my mail provider at work doesn't support submission 
over 587. Can you say "ssh tunnel back to my home machine"?

Toby DiPasquale
Philadelphia Linux Users Group         --
Announcements -
General Discussion  --