I've just tried new.net's plugin. Don't.

Sat Mar 17 05:20:13 UTC 2001

On Fri, 16 Mar 2001 20:46:55 PST, Aaron Hopkins said:
> Even though this isn't in place for *.com, the typo-squatters catch the
> common mistakes anyway; DotTV and new.net at least also provide MX records
> that immediately bounce all mail.

Two words:  Scaling Issues.

I saw recently that the root nameservers are currently running a flux of
10K-20K packets *per second*.  *each*.  Figure that there's 13 root servers,
and they only see when a resolver needs to be reminded where .com, .org, .net
are served from, so there's a lot more queries than THAT going on.

Also, remember that bad queries probably make up an inordinate percentage
of the lookups at the root and TLD levels - my local DNS already has cached
the NS entries for the .COM tree and most of the foo.com's that I talk to.
So it won't be recursing up for me unless I ask for broken.com or is-ok.comm
or something like that.

Now remember that a negative query reply will be on UDP in and one out.

Buoncing the email immediately requires a minimum of 17 packets if you
accept the mail (and 17 more later if you send a reply).  You can get down
to 13 packets if the host doing it blindly returns '550 User/host unknown'
for each RCPT TO:  But at that point, why bother having the MX?  Leave it
out, and let their resolver and their mail relay give the 'host unknown'
error without any further load on YOUR resources above the 2 UDP packets.

				Valdis Kletnieks
				Operating Systems Analyst
				Virginia Tech