[LINK] BigPond goes Static

[Craig Sanders]

On Wed, Jan 21, 2004 at 12:44:45PM +1100, Ash Nallawalla wrote:
> > On Tue, Jan 20, 2004 at 03:54:53PM +1100, Ash Nallawalla wrote:
> > > I have located people with fixed IP addresses because their email 
> > > headers over time are unchanged.
> 
> > people don't have fixed IP addresses.  machines do.  
> 
> I know.  The ones I referred to are companies whose networking regime is known to
> me (fixed IP addresses).  While that CEO's secretary or wife may well surf the web
> from his PC and know his password, I don't think she would visit my site from his
> PC.

people don't have IP addresses.  machines do.  assuming otherwise is a mistake.


> > at the very least, you should understand the limitations of what you are
> > doing and not be surprised - or upset - when your mail gets rejected
> > because it is coming from a dynamic IP address....because it WILL get
> > rejected for that reason.  there is just too much spam and too many viruses
> > coming 
> 
> Why shouldn't I be surprised?  

because many sites do not accept mail direct from dynamic IP addresses.  They
use DUL RBLs or other methods to identify connections from dynamic addresses.

> I am *trying* to understand Outlook 2003 and its "limitations", (oh woe is
> me, it is not Open Source).  The above test suggests that it checked the DNS
> and didn't bother to send it to my SMTP gateway.
> 
> To use a supposedly cooler mail client, Agent, doing the same results in a
> popup stating a 450 error, not a bounce email.  I can't replicate the error
> with the blacklisted address.

it has nothing to do with the client.  mail from dynamic ip addresses will be
rejected regardless of whether it's sent by a mail user agent like
outlook/eudora/mutt etc or a mail server such as postfix or sendmail or
exchange.

4xx error codes indicate "temporary failure, try again later".  Outlook should
NOT bounce a message on a 450 error, it should put the message back in the
outbound queue ("Outbox" or whatever it's called) and optionally alert the user
with a popup dialog.


> So, to extrapolate, Netspace did such a good job by using the black list to
> manage its outbound mail, that it blocked me from sending an email to its own
> Helpdesk.

that's dumb.  they should know their own IP address ranges, so they should
easily be able to exclude them from RBL checks - that's standard procedure for
any ISP (or other mail server) using any of the RBLs.

craig