Sendmail weirdness

[dmartin at LanCity.COM (Derek Martin)]

On Wed, 20 Oct 1999, Mark Donnelly wrote:

> 
> > >>> RCPT To:<dkatz at dhcp-250-11.kenan.com>
> > 550 <dkatz at dhcp-250-11.kenan.com>... Relaying denied
> 
> Do you notice a difference here?  What's going on is that somehow cam-katz
> is getting translated into dhcp-250-11.kenan.com.  Assumedly, cam-katz
> doesn't know about the dhcp* name, so it's rejecting the mail, on the
> reasoning that someone is trying to use it to send mail to another machine
> (also known as relaying, a favored technique of spammers).
> 
> This is both a configuration problem (due to DNS issues, or not listing
> all the recognized names in the proper /etc/mail/* file under RedHat), and
> a security problem (trying to stop the spam).
> 
> To fix it, I'd suggest either getting bishop to recognize cam-katz as
> such, or add dhcp-250-11.kenan.com to the appropriate /etc/mail/* file.  I
> think that there might be another option - configuring it to accept mail
> for all of kenan.com - but that might not be what you want.
> 
> > dkatz at cam-katz... User unknown
> 
> I'm guessing this is the friendly error message from /bin/mail that
> corresponds to a 550 SMTP error code.

Yep, I agree 100%.  

The file to add the name to is /etc/sendmail.cw on RedHat, at least on 6.0
-- I can't say if it's the same on all versions...


*******************************
|       Derek D. Martin       |
|  UNIX System Administrator  |
| derek.martin at ne.arris-i.com |
*******************************

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