Very Computer

Could anyone tell me how to stop Solaris 7 from performing reverse DNS
lookups for incoming client connections please?
The process of it doing this to our PCs in a WINS and DHCP environment
is slowing down connections to the server to an unacceptable level.
The reverse lookup serves no purpose as the PC's have no host entries in
the DNS database.
They are connecting via telnet and http to Netscape Enterprise server.

Thanks

nsswitch.conf has his entry for hosts
hosts:      files dns

Quote:>Could anyone tell me how to stop Solaris 7 from performing reverse DNS
>lookups for incoming client connections please?
>The process of it doing this to our PCs in a WINS and DHCP environment
>is slowing down connections to the server to an unacceptable level.
>The reverse lookup serves no purpose as the PC's have no host entries in
>the DNS database.

I'm not aware of any way to keep telnetd from doing this.  But it should
only slow things down if the server for the reverse domain doesn't respond.
You can solve this by creating a reverse domain, and simply leaving out the
PTR records; you'll get back an immediate response that says that the
reverse record doesn't exist, and that will satisfy telnetd.

--

Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

So what's the point of the reverse lookup then?

Probably so the hostname can be logged in /var/adm/utmpx and wtmpx
for reporting by the "who" and "last" commands.

The point is that it does something useful if you're coming from an address
that does have a reverse DNS entry.  There are three cases to consider:

1) There's a reverse entry for the address.  In this case, commands like
   "who" can show the hostname.

2) There's a reverse DNS server for the network, but it has no reverse
   entry for the address.  "who" will show the address instead of the
   hostname.

3) The nameserver that the reverse DNS is delegated to doesn't exist.  In
   this case, the resolver keeps trying to query it for about 30 seconds
   (it can't tell the difference between a server not existing and
   temporary network problems), and then times out and treats it like case
   2.

Case 3 is the one that screws up many sites, resulting in a 30-second delay
between telnet saying "Connected" and getting the login prompt.  The
solution is to change to case 2 by putting the reverse domain on your DNS
server, but leaving out all the PTR records.

--

Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.