[NCLUG] Easy sendmail security question

[dobbster]

Charles Clarke wrote:
> 
> If it is like the ones I get, it indicates that your sendmail checks
> are working.  Check the lines above and below the Null connection ones.
> 
> Jun 24 01:16:48 ns sendmail[22875]: NOQUEUE: ruleset=check_relay,
> arg1=s1.universalmaster.com.tw,
>  arg2=210.71.162.33, relay=s1.universalmaster.com.tw [210.71.162.33] (may
> be forged), reject=553
> Blackhole:open spam relay 210.71.162.33 see:http://www.mail-abuse.org/rss/
> 
> Jun 24 01:16:49 ns sendmail[22875]: NOQUEUE: Null connection from
> s1.universalmaster.com.tw [210.71.162.33] (may be forged)
> 
> These two lines indicate that my machine blackholed a message and
> so the other side dropped the connection.
> 
> charles

This is evidently what's happening in my case.  Sometimes I receive multiple
Null connection messages.  I think I understand what's happening here, more or
less - I get the same results from a "telnet dipole 25", and outside of the
subnet, it just closes the connection.  Good!

Thanks for the reassurance!

Mark