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From: paul@uxc.cso.uiuc.edu (Paul Pomes - UofIllinois CSO)
Newsgroups: comp.protocols.tcp-ip.domains
Subject: Re: no inverse mappings
Message-ID: <1990Aug10.162416.22650@ux1.cso.uiuc.edu>
Date: 10 Aug 90 16:24:16 GMT
References: <1990Aug10.152144.17260@ee.rochester.edu>
Sender: usenet@ux1.cso.uiuc.edu (News)
Organization: University of Illinois at Urbana
Lines: 27

deke@ee.rochester.edu (Dikran Kassabian) writes:

>[Re: non-existent in-addr.arpa entries]
>
>Are others seeing this?  What do you do about it?  Ignore it?  Send mail
>to the hostmaster or postmaster of the parent registered net?  How about
>refusing such connections altogether when the address doesn't inverse map?
>I'm willing to continue ignoring this for now, but I'd like to hear from
>others... what is the Right Thing To DO?  I guess I'm hoping someone more 
>knowledgeable than I will quote an RFC and make it all better :-\

On the machines I administer, ftp/telnet/rsh/etc have been modified to reject
connections from IP addresses that can't be inverse mapped.  An informative
message is printed in some cases (ftp) that says why and what to do about it:

421 Cannot map IP address into host name.  We only accept FTP connections
    from recognized sites.  Get your system administrator to fix your domain
    servers or try again in a few minutes when the DNS has the translation.

Uunet does about the same thing.

/pbp
--
         Paul Pomes

UUCP: {att,iuvax,uunet}!uiucuxc!paul   Internet, BITNET: paul@uxc.cso.uiuc.edu
US Mail:  UofIllinois, CSO, 1304 W Springfield Ave, Urbana, IL  61801-2987