Reverse DNS Lookup

[David T. Smith]

At 04:05 PM 6/2/99 -0400, Matt Wade wrote:
>Thanks for the quick reply.
>
>The remote IP address that's giving me trouble is: 209.220.225.26.
>
>When I do an nslookup here's what I get:
># nslookup 207.172.111.120
>Server:  cameron.dcaccess.net
>Address:  209.220.225.26
>Aliases:  26.225.220.209.in-addr.arpa
>
>Name:    207-172-111-120.s120.tnt1.ann.va.dialup.rcn.com
>Address:  207.172.111.120
>
>I get this response immediately. So it seems to me that their IP address
>is mapped OK, right?
 207.172.111.120 seems to be cached on your DNS server. 
That would give you a quick response (and it should make your FTP
connection also quick).  If your FTP connection is not quick, then 
there are a few other issues to look at:

	When the client on 207.172.111.120 connects, does the 
	initial "Connected to " appear immediately, with a 
	long wait for the "Username"?

	Do you get the same slowness connecting to other services
	that might have inverse lookups associated with them?
	Telnet?  HTTP? SMTP?

	Is there a firewall that does its own logging in between?
	Can it resolve the addresses?

There are other things to look at, but the problem is beginning
to drift far afield from the topic of this newsgroup and might 
be pursued better off line.

DTS


D A V I D  T .   S M I T H 
Principal Consultant, Network Solutions 
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