Host name not getting resolved

[jayachandran.g]

Hi all

I have two servers in cluster. SRV1 and SRV2.One of the processes in SRV2 server is trying to get the hostname for the SRV1 servers ipaddress.

The Error: Unable to get the hostname for the ipaddress 10.1.1.1 (10.1.1.1 is the SRV1 ipaddress)

I have checked the /etc/hosts file, found that the ipaddress and the host name for this ipaddress is missing in both the servers.

Then I have added the ipaddress and host name in both of the servers.

But then too problem is not solved.

help me, thanks in advance

[RAC_1 · Accepted solution]

Do both servers use /etc/hosts for host name resolution? Check /etc/nsswitch.conf file.

[Victor BERRIDGE]

Hi,
Have you checked your /etc/nsswitch.conf file and /etc/resolv.conf, their perms and for nsswitch.conf if you do have something like:
hosts: files [NOTFOUND=continue] dns

Are these addresses correctly routed?
(correct subnet route, netmask..)

What are the perms on your hosts file? (444)

All the best
Victor

[jayachandran.g]

Hi RAC/Victor

There is no nsswitch.conf (or) resolv.conf file in the servers.

I have already checked and rectified the host file.

entry for the ipaddress 10.1.1.1 was missing previously.And I have already added the missing Ipaddress to the host files.

[Darrel Louis]

Hi,

Have you added the servers to the /etc/hosts file asfollow:

10.1.1.1 srv1.domain.com srv1

And as already mentioned check your /etc/nsswitch.conf file.
If the file doesn't exists copy it.
# cp /etc/nsswitch.files /etc/nsswitch.conf
Modify the line hosts:
hosts: files [ NOTFOUND=continue ] dns

Goodluck

Darrel Louis

[MarkSyder]

You will probably have a file /etc/nsswitch.compat, which can be copied to nsswitch.conf.

You should set it up so it uses files first for hosts.

Mark Syder (like the drink but spelt different)

[Victor BERRIDGE]

Hi again!
What servers and most important what cluster are you talking about?
It may be nothing to do with the servers themselves but more the way a process is looking for his "hostname"...
A cluster like mcSG will have on a host ist address (HW-server) + the addresses of the packages running on it....

All the best
Victor

[Frank de Vries]

Otherwise you can create the nsswitch.conf
in the /etc directory and put this
contents in it

hosts: files [NOTFOUND=continue UNAVAIL=continue] dns [NOTFOUND=return UNAVAIL=continue TRYAGAIN=return]

If will first check your local /etc/hosts
and then check your dns

You can troubleshoot with nslookup command:

I have a host called frank only in /etc/hosts
10.214.9.118 frank

When I use nslookup it will show where it
resolved it.

[orapic@orasrv1:]/etc<>>> nslookup
Using /etc/hosts on: orasrv1

> frank
Using /etc/hosts on: orasrv1

looking up FILES
Name: frank
Address: 10.214.9.118

>

Good luck

[jayachandran.g]

Hi All

Host name to IP address maping is working fine.

Ip to Hostname is not working.

Regards
Jayachandran.G

[spex]

Hi,

Try using nslookup to do reverse DNS:

# nslookup
# nslookup

If the IP address is resolved correctly, try restarting the processes. This will force them to re-read configuration.

Did you create /etc/nsswitch.conf and /etc/resolv.conf ?

PCS