Russian incursion... to my bulletin board.

[Ken D'Ambrosio]

Hey, all. I belong to the last of a dying breed, a bulletin board.  (No, 
we no longer do dialup; it's accepted telnet since '90 or so.)  And it's 
currently under the purview of someone, though he hasn't been able to 
give it the attention it needs, so I think it's about to go to Digital 
Ocean.  (Indeed, as I type this, it's offline -- which is responsible 
for the whole line of thinking for this e-mail.)  Migration would 
normally be unremarkable, and not require an e-mail here, but... the 
damn Russian botnet problem (the one that brought Dyn down last year) 
has also caused us an issue.  The current admin has largely mitigated it 
through blacklists, but I was wondering if there might be a more 
graceful approach.  Issue: the botnet attempts to expand by searching 
for other embedded devices (generally, cameras)... by way of port 23.  
Telnet.  At any given time, we may have a dozen bogus connections from 
botnets, all trying to log in as "admin".  Of course, they fail, but 
they chew up ports, and seem to even have uncovered a bug in the BBS 
code, just by raw number of connections.  Can anyone think of a way to 
act as a proxy and:
* Accept a telnet connection
* Offer a login prompt
* Reject/close the connection if the username offered is "admin"
* Forward on the connection/credentials and act as a proxy if it's 
literally anything else?

I've taken a stab at it in Ruby, but seem to have issues understanding 
exactly how the telnet module works...

Thanks kindly for any thoughts or insights,

-Ken

P.S.  If/when it comes back up: telnet://bbs.iscabbs.com if you're that 
interested in logging in like it's 1993.  Apologies to Prince.