Connection Problem

[Smirjit Singh]

Today I got a strange problem. We have a D class server with two lan card. External is 208 segment & internal is 172 segment. In our primary nameserver external Ip address is registerd. So when our internal user tries to ping that server then they get external ip address.

Today I configured DNS on that server. When I have changed resolv.conf & put primary & domain name server. Then from internal network when user's was trying for telnet or ftp . It got strucked for near about two minutes. But when I delete nameserver line from resolv.conf then they was able to connect very quickly. It was showing connected at port ... & stucked for near about 2 minuts.

Now my question why it is happening. Why telnet & ftp would depend on NAMED. Would anybody pls clear my doubt on this matter.

Sandip

[RikTytgat]

Hi,

Everything requiring translation from hostname to ip address uses DNS (and hence named), if activated. The routines actually doing the lookup is called the 'resolver'. Depending on some configuration files (nsswitch.conf), it tries to find an ip address from the hosts file or from DNS.

For that matter, even a ping uses DNS if the host is configured to use DNS.

Does this answer your question??

Bye,
Rik

[Rita C Workman · Accepted solution]

Here's a thread that explains it too....

http://us-support.external.hp.com/cki/bin/doc.pl/sid=0ca6086d1a8af7533e/screen=ckiDisplayDocument?docId=200000027709160

/rcw

[John Bolene]

The user must have been connecting to the named machine which probably exists only in the hosts file on the server. Try putting the hosts file entry first in /etc/nsswitch.conf to resolve local entries before external entries.
The data in this file may look something like:
hosts: files [NOTFOUND=continue UNAVAIL=continue TRYAGAIN=continue] dns [NOTFOUND=return UNAVAIL=continue TRYAGAIN=return]

[Smirjit Singh]

Hi Rita,

Thanks a ton for that link.

Yes the problem was same as described in that link.

Sandip