topic Re: Revers DNS lookup in Operating System - HP-UX

Revers DNS lookup

Sergejs Svitnevs — Wed, 21 Sep 2005 01:29:08 GMT

Hello

Our app server tries to reverse lookup the connection query to find out the server name and all requests to that server are delayed by 10-15 sec.

Unfortunately, I can not change outdated reverse lookup records in DNS and can not disable reverse dns lookup for my app. Is it possible to manage private Reverse IP lookups through files contained simple list of computer names and associated static IP?

Thanks

Re: Revers DNS lookup

Alex Lavrov. — Wed, 21 Sep 2005 01:33:52 GMT

Yep,

just populate your /etc/hosts file with the entries and make sure that in /etc/nsswitch.conf in hosts line files comes first.

This way it will first check in files and it will be very fast.

Alex.

Re: Revers DNS lookup

Muthukumar_5 — Wed, 21 Sep 2005 01:42:01 GMT

Basic setup to use /etc/hosts file with hosts: entry setting in /etc/nsswitch.conf.

Change hosts: entry as,

-- /etc/nsswitch.conf --
hosts: files

-- /etc/hosts
127.0.0.1 localhost loopback
ip-address fqdn hostname

It will do your need. Just copy this /etc/hosts file setting to all available machines in the network.

Check routing entry for this also If machine is not reachable.
# netstat -rn

hth.

Re: Revers DNS lookup

Arunvijai_4 — Wed, 21 Sep 2005 01:47:38 GMT

Edit your /etc/hosts and add your static IPs there. It should do.

-Arun

Re: Revers DNS lookup

njia_1 — Wed, 21 Sep 2005 01:48:49 GMT

Hi

I had this problem as well, adding hostname to /etc/hosts is not a good solution because the ip address and hostname are keeping changing. New hosts could be added to the network everyday.

Re: Revers DNS lookup

Sergejs Svitnevs — Wed, 21 Sep 2005 01:51:43 GMT

From my point of view I can use /etc/hosts file for Forward DNS lookup (hostname->IP)only.
Reverse IP address lookup converts the IP to the name and '/etc/hosts' file does not support this future.

Re: Revers DNS lookup

Muthukumar_5 — Wed, 21 Sep 2005 03:10:57 GMT

/etc/hosts will be able to reverse lookup too. (ip-address --> hostname)

--- /etc/hosts ---
127.0.0.1 localhost loopback

# nslookup 127.0.0.1
Using /etc/hosts on: hostname

looking up FILES
Name: localhost
Address: 127.0.0.1
Aliases: loopback

It will return localhost and loopback there on configuring hosts: files there.

It is showing that it is doing R-Lookup too.

hth.

Re: Revers DNS lookup

Alex Lavrov. — Wed, 21 Sep 2005 03:11:31 GMT

It does.

host->ip and ip->host, works both with /etc/hosts.

Alex.

Re: Revers DNS lookup

Sergejs Svitnevs — Wed, 21 Sep 2005 04:00:02 GMT

Thanks