So far,why reverse DNS doesn't work seems to be a mystery. But
we did isolate one factor.
If you try to do a reverse DNS from a W95/98 computer (ping -a #.#.#.#)
the DNS works. But only if the "node type" says hybrid when you run
winipcfg, if it says anything else (we had one that had "broadcast" as
the node type) then the reverse DNS doesn't give the machine name.
This part is OT, but, what determines the node type on winipcfg?
Now for the fun part (on back on topic), is there anyway to make DU
(3.2c)
tulip 10mb/sec card) be a "hybrid"?
Forward DNS works fine, however, telnet attempts to do a reverse DNS on
login, and when it tries, it hangs up the login process.
If I use nslookup and attempt a reverse DNS, then it displays back,
server failed
from a linux machine on the same network/subnet, doesn't work either,
but it
says the server can't find the IP in question.
It (the DNS server - NT machine) will however resolve reverse IP that
are
hard coded, it seems that the ones DHCP (again another NT machine)
assigns
are the ones it can't find.
The ONLY factor apparantly that started this, was the firewall was
rebooted,
BUT, all the equipment in question are all on the same side of the
firewall.
Thanks
George Gallen
ggallen_at_slackinc.com
> -----Original Message-----
> From: George Gallen [mailto:ggallen_at_slackinc.com]
> Sent: Friday, June 04, 1999 10:26 AM
> To: 'tru64-unix-managers_at_ornl.gov'
> Subject: dns/telnet conflict
>
>
> We had this problem start yesterday.
>
> We are running DU 3.2c on a 2100. Our DNS server is on an NT network.
> People telneting/FTPing are from W95 machines on the NT network.
>
> When someone would telnet either it would take a about a
> minute for the
> login
> prompt to come up or would never come up. FTP would come back as call
> blocked.
> The only people that could login were those who were specifically
> defined
> in the /etc/hosts. Since I'm using TCPwrappers, it was trying to do a
> reverse
> DNS on telnet logins (which is where I believe the hangup was from).
>
> Once I removed the DNS entries from my /etc/resolv.conf, then
> the logins
> were
> fine (tcpwrappers was not compiled in Paranoid mode).
>
> Here's the problem.
> If I disable the tcpwrappers, however, I'm still getting
> telnet hanging
> on logins, if I rename my resolv.conf file (disabling the DNS), the
> logins
> work fine, except now we can't send email (can't resolve the
> addresses).
>
> What is causing telnet to do a reverse DNS and is there any
> way to stop
> it
> but still allow dns service for our email system
> (sendmail/mailx), aside
> from
> defining each IP address in the /etc/hosts file for all users.
>
> George Gallen
> ggallen_at_slackinc.com
>
Received on Wed Jun 09 1999 - 20:07:05 NZST