[SpamCop-List] Re: Comcast considers "clever" anti-spam idea

[Rolf]

KronaTech wrote:

> They can't block 25 outbound by default or nobody would be able to
 > use their remote mail, such as their business mail from work.

They could and a lot of ISPs here (both ADSL accesses I use at home and 
at work at least) in the Netherlands just do that. You could most 
probably try to get your IP address excluded from that but I found it 
easier to just setup two outgoing mail accounts with the SMTP server of 
each provider on it and activate the one I'm on.
Another option is to have such a business mail server provide an 
authentificated SMTP port on one of the RFC ports for that matter. IMO 
relaying on non-authentificated SMTP access for remote mail users is 
simply one of the reasons spam is possible and as long as that doesn't 
change there is not much hope that we ever can fight spam effectively in 
the technical area and we are bound to hope that legislation gets of its 
lazy butt to do something about it.

 > Blocking it (outbound) on occasions of malice will only work when the
 > infected/affected machines actually use 25. Those machines can just as
 > easily use any other port to connect to a proxy on another network, which
 > would use 25 outbound on their behalf.

They could and probably will do that after some time, but it still 
reduces the number of spew servers which can directly spam. After all 
such a zombie is not as much worth as one which can directly spew and 
once all networks would block (one can dream) there would be no proxies 
left other than the ones provided by spammers and spammer friendly 
networks. But they would be blocked easily.

> If they block 25 inbound by default, that's their right as long as they
> provide the information in their service agreement, but it will only effect

I was refering to outgoing here. I understand the ineffectivity of 
blocking incoming port 25 for spam fighting purposes. The only reason an 
ISP would want to do that is to prevent its users to actually run their 
own mailservers.

Rolf Kalbermatter