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nslookup hangs in a lead of a domain in Sierra Cluster

S.P.Ganesh
Occasional Advisor

nslookup hangs in a lead of a domain in Sierra Cluster

i have a 8 node SC cluster with a management server and a lead node having external IP which can contact outside network. The DNS resolve is fine in mgmnt server whereas the lead node fails to resolve any names.. Even if there is a entry mapping in /etc/hosts file it dosent ping or reslove the name. I have checked the nsswitch.conf,svc.conf and /etc/gateways and all relevant files and found to be fine.

Could anyone give suggestions on this?

Regards,
Ganesh S.P.
7 REPLIES
Ivan Ferreira
Honored Contributor

Re: nslookup hangs in a lead of a domain in Sierra Cluster

Can you post the results of:

/etc/nsswitch.conf, /etc/svc.conf, /etc/resolv.conf.

nslookup hostname

ping hostname
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
S.P.Ganesh
Occasional Advisor

Re: nslookup hangs in a lead of a domain in Sierra Cluster

hi,
thanks for immediate reply. i m posting the required files for your reference..
the dnscase.zip file contains the required files

thanks,
ganesh
Ivan Ferreira
Honored Contributor

Re: nslookup hangs in a lead of a domain in Sierra Cluster

You did not posted the ping and nslookup commands.

If you want to specify multiple domains in the /etc/resolv.conf file, you should use:

search mydomain.com mysubdomain.com


Instead of the domain option. That is incorrect in your /etc/resolv.conf configuration file.
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
S.P.Ganesh
Occasional Advisor

Re: nslookup hangs in a lead of a domain in Sierra Cluster

my management server has the similar entries in resolv.conf and other files but still it works fine. i am attaching nslookup,ifconfig -a and netstat -nr output..ping to any server by name hangs.
Ivan Ferreira
Honored Contributor

Re: nslookup hangs in a lead of a domain in Sierra Cluster

From the output of nslookup:

fc0 # nslookup
*** Can't find server name for address 16.150.35.242: Timed out
*** Default servers are not available

It's possible to see that you cannot reach the DNS server.

You should test if:

Can you ping to that DNS server 16.150.35.242?

Can you connect to port 53 of the 16.150.35.242 host?, try with:

telnet 16.150.35.242 53

You should get a response like this:

Trying 16.150.35.242...
Connected to 116.150.35.242.
Escape character is '^]'.

If you cannot ping, there is a connection problem between your server and the DNS server. Maybe some route missing or firewall blocking the access.

If you can ping but cannot telnet to port 53, you can reach your DNS server but cannot connect to the service. Check your firewall configuration and also your DNS server configuration. The DNS server could be blocking connections from that host.
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
S.P.Ganesh
Occasional Advisor

Re: nslookup hangs in a lead of a domain in Sierra Cluster

I am able to ping from the machine to DNS server by ip. if i do a telnet 53 it hangs there and no response. but my lead node is also under same subnet and similar network config and it is able to reach the DNS Server. I dont see a problem of Firewall because both the machines are under same network.

Could you please suggest on this?

thanks,
Ganesh S.P.


Ivan Ferreira
Honored Contributor

Re: nslookup hangs in a lead of a domain in Sierra Cluster

In this case, the only way to go is to use tcpdump on the DNS server and your server to identify what is going on with the packets. See "man packetfilter", you must create the pfilt devices, use pfconfig +c to enable the capture and then use tcpdump to view the connections, like this:

tcpdump -n -l -f -i port 53
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?