PC Telnet and DNS

[Michelle Barton]

I have finally figured out, through all of the input in the forums, that our reverse lookup was not working properly. I corrected all of the host name problems, but am still left with PC slow connection. What do I do to correct slow pc telnet access? Do I have to define all possible IP's for pc's?

Your help is greatly appreciated.

Michelle

[Albert E. Whale, CISSP]

I owuld certainly insure that every address in your domain is in DNS. Some OS's will not allow a connection (e.g. IBM's AIX) unless it can authenticate the IP Address in the DNS. Let's face it, more and more it becomes easier to Spoof an IP Address.

I would HIGHLY recommend the investment in time involved in updating DNS.

Have a Great Day!

[Shannon Petry]

I second what Albert stated very well. However the problem may really be a Windblows recourse location problem because Windblows can not resolve the host it's telnetting too. So you have then three choices.
Update DNS and use DNS for Wins on your PC's, Setup Wins for your PC's or make host files and put them in
c:\\windows (95/98/ME)
c:\\winnt\\system32\\drivers\\etc (NT4/2000).

Keep it simple and use DNS :-)

Regards,
Shannon

[Ian_4]

What NT version are you using? Are you running WINS, DNS or simply adding the entries in a hosts file? Are you telneting from NT to NT (using win2k or special apps) , from NT to Unix or from Unix to NT? What node you have ( b-node, p-node, m-node, and h-node)

You need to identify if your problem is caused by slow IP address resolution to a TCP/IP hostname ?OR- IP address slow name resolution for a NetBios name (computer name) - The symptoms for name resolution issues will be like it take a long time to get a telnet session established. Generally telnet should take < 2 ?3 seconds to get the connection established, if your DNS, WINS or hosts file are properly configured. Run nslookup (or the debug nslookup ?d2 option) to verify the time it takes to get the connection established. If the session takes more then 2 to 3 seconds then you have a name resolution delay, and you need to add the entries of the nodes to WINS, DNS or hosts file. - Microsoft TCP/IP network had an unpleasant pair of options for NetBIOS over TCP/IP name resolution: They could either rely on broadcasts or construct a static name resolution table, lmhosts & hosts. So make sure that you are using DNS and or WINS (and you have SP6a loaded on all your DNS servers and clients!)

- Adding the TCP/IP and NetBios names to DNS will definitely speed up the name lookup if DNS is properly configured.

If the problem is with slow performance after that the telnet session have been established, then it?s not a DNS or WINS issue.

hope this helps,
Ian

[Wodisch]

Hello Michelle,

be careful about name resolution on Windozes...
It tries NetBIOS first! Hence put in your names
and IP-addresses into your PC's local "lmhosts" file.
Usually in "\WinNt\system32\drivers\etc\lmhosts".
That file normally just does not exist - you have to
create it!!! Syntax like "hosts" on your unix.
Read the comments in "lmhosts.sam" on your PC.
Check your NetBIOS cache with "nbtstat -c".
HTH,
Wodisch