[PLUG] Postfix relaying...

[Michael C. Robinson]

I forget how to detect if a postfix server is an open 
relay.

I've gotten a null client going, but I'm wondering how 
set up relaying or secondary exchangers for my mailhub.  



The strange thing on my gateway is that I was blocking 
loopback traffic yet it was still working.  Couldn't 
figure out why the host lookups to my fast gateway's 
internal dns were so slow.  I figure my 386 server 
shouldn't outrun a Pentium III. :-)

If I queried my fast gateway's dns when loopback was 
blocked from another server I could resolve names quite 
fast.  Why would you block 127.0.0.0/8 addresses?  That 
must have been a mistake in the iptables firewall I was 
looking at.  As far as what test-net and other blocks
are that are "bad," where can I get a good list to verify
the other rules in this firewall?  I've done some change
to it which makes it easier to see what rules go to which
protocol at the expense of multiple files instead of just 
one.  Then again, the sourcing section where I stamp
in the other files gives a quick glance at supported
protocols, which is nice.  I'm not a big fan of long
scripts or programs anyways.  On the upside, my 
add/remove forwarding for a single host command works 
quickly for the first time as I'm not waiting to time out
anymore every time I run it.

BTW, I have the source tree I installed sendmail-8.12.9 from.
Is there an easy way to remove the files sendmail installed
from a make command or something in case I missed one?
I could do rpm -qf on every file on the hard drive, but 
there could easily be a lot of files that aren't owned 
by any rpm.

I installed Redhat 7.3's Postfix to Redhat 7.2, seems to
work right.  I had to replace chkconfig with the
7.3 version along with db3 and db3-devel to get Postfix on
there.  After that, I manually created the same accounts for 
Postfix that were on an actual Redhat 7.3 server right down
to the user and group ids.

     --  Michael C. Robinson