Possible lost DNS connection

[dklloyd]

We have an application running on the AIX server that uses DNS lookup constantly to send data from an Oracle database back to the client. Every now and then we are getting errors when the application cannot resolve the IP address and we therefore assume that the server or application has momentarily lost contact with the DNS server. Unfortunately owing to timeouts either in the application or UNIX port, this causes the port to hang for 10 mins every time this occurs.

Can anyone suggest a way of tackling this problem, to find out why or where the problem emanates from?

Many thanks in advance.

dklloyd

 

[gheist]

There is no "connection" in DNS - it uses UDP datagram exchange

You can disable bind name resolution for oracle and many apps by creating
/etc/netsvc.conf
with one line
hosts=local

 

[avadh]

Hello,

The right steps are
vi /etc/netsvc.conf
hosts=local,bind4

look at local host file first then, DNS and use tcp ver 4.0 and not tcp ver 6.0

 

[dklloyd]

Sorry should have explained the set-up more. We are using netsvc.conf as you suggest & host=local,bind4 in order to use the NT4 DNS server. It's just that every now & then the application is not able to resolve the PCs IP address to send the messages back to the PC.

THe application is very lookup intensive.

I'm really looking for suggestions how I might be able to monitor where things are going wrong when they do go wrong. So far we find out after the event has happened and cannot trace where the problem is coming from... either the UNIX server, the gateway or the DNS server.
THe DNS server is not recording any issues in its event log.

Thanks again

dklloyd

 

[gheist]

check if your nslookup works -what is the response when it starts to fail (on aix)

You can install local caching nameserver as nt may not handle its work at the necessary speed

check bind samples on

http://www.isc.org/

for caching nameserver (BIND section)

 

[gheist]

do you have a real DNS server running or NT??? - or just nothing or WINS???

 

[dklloyd]

Thanks..
we have a real NT DNS server that the server is using. There is a WINS server also on the network that synchronises with the DNS.

dklloyd

 

[gheist]

then check isc.org on how to make another caching (or even secondary) nameserver on aix