topic Re: port locked? in Operating System - HP-UX

port locked?

Francis Hwang — Thu, 31 Jan 2002 18:42:27 GMT

When I issue "netstat -a" it displays one line every 12 or more seconds. Something is wrong on this HP-UX 11.0 box. Network response, ping, telnet, ftp all seem ok. Except some users login from RF device have to wait 30 second to get connected. But once connected, all work fine. Do anyone has any clue?

Re: port locked?

harry d brown jr — Thu, 31 Jan 2002 18:44:02 GMT

What is an RF device?

live free or die
harry

Re: port locked?

Francis Hwang — Thu, 31 Jan 2002 18:48:28 GMT

RF stands for Radio Frequency. Typical use is wireless bar code scanner for inventory purpose.

Re: port locked?

John Jimenez_2 — Thu, 31 Jan 2002 19:17:01 GMT

Francis,

I had this problems plus lockups when I used a 3com card with aironet (cisco) antanas. At that time I had only 3 people using them. I swapped them over to cisco and that worked great. I guess my problem had to with compatibility. Is you RF card and antaneas made by the same company. If not try another vendors card. Also if you are using encrypten instead of clear text I guess it could be authenticating. But, as long as you work fine one you are on the network, Is sounds like a small price to pay for

Re: port locked?

Krishna Prasad — Thu, 31 Jan 2002 19:45:25 GMT

Can you do a traceroute from your box to one of you RF devices? This is of course if they have an IP. I know some RF devices get there IP from a base station or some other device.

If the gun it self doens't have an IP try doing the trace route between your host and the RF/BASE station.

This might help you determine which connection is having trouble.

Re: port locked?

harry d brown jr — Thu, 31 Jan 2002 21:31:52 GMT

Yup, that's what I consider RF. I just wasn't sure if RF had taken on a new meaning.

live free or die
harry

Re: port locked?

Francis Hwang — Thu, 31 Jan 2002 21:49:26 GMT

John & Ron,

Thanks for your response. Routing is not a problem since they sit on the same switch. And there is another server in the same subnet running without any problem. I can reboot this server and that may clean up everything. But I want to keep the problem there so I can find out what's wrong. The netstat -a delay leads me toward problem of the port/socket hangs. But I don't know how to analyze this kind of situation. Any help will be greatly appreciated!

Francis

Re: port locked?

Ron Kinner — Thu, 31 Jan 2002 22:15:51 GMT

Compare the response time of netstat -a with netstat -an. Do you see a much faster response with the -an option? If you do then you have a DNS problem and the delay you are seeing is the timeout when it queries the DNS for the hostname associated with the ip address.

Try using nslookup to find the name of a device (at ip a.b.c.d) on your network by typing:
nslookup a.b.c.d

Do you get a result? How long did it take? About as long as your time between lines on netstat -a? Per the 10.2 man you should have files: /etc/resolv.conf where the DNS server is defined and /etc/nsswitch.conf where it defines the order of query (DNS then /etc/hosts or NIS).

You can also type nslookup by itself and I think it should tell you where it will try to get the info from first. Get out of interactive mode with exit. I don't use DNS on my systems so it just goes to /etc/hosts and pulls out the name really fast.

Ron

Re: port locked?

Francis Hwang — Fri, 01 Feb 2002 19:10:58 GMT

Ron,

You got it!
netstat -na came right back. I checked DNS boot file and found there was no forwarders entry. Changed boot file and restarted the DNS server. Everything works fine now. Great help! Thanks!

Francis