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Setting up net-snmp or snmp on HP-UX 11.31 to connect to Whats Up Gold

TroyBlang
Occasional Advisor

Setting up net-snmp or snmp on HP-UX 11.31 to connect to Whats Up Gold

Hi

 

I would like to work with someone on my issue of having the net-snmp timing out on my HP-UX 11.31 server that should be connecting to a third party software on a Windows Server called Whats Up Gold.  If anyone knows how to resolve the issue of why I am getting timeout issues on my HP-UX server but the same configuration is working on a Red Hat Linux server on the same subnet please contact me.  It looked like Matti Kurkela was sending me a post on my issue.  I also saw that Michael O'Brien set up HP-UX to the software Whats Up Gold.  Hopefully you guys can help me get this resolved.  Any one else that can think of why this is not working can help me too.  I am at a loss why it is working on the Linux server but not HP-UX.  Please help me out.

 

Thanks

Troy

6 REPLIES
Dennis Handly
Acclaimed Contributor

Re: Setting up net-snmp or snmp on HP-UX 11.31 to connect to Whats Up Gold

It would have been helpful if you included a link to your previous topic or even better, continued it:

http://h30499.www3.hp.com/t5/System-Administration/net-snmp-on-HP-UX-11-31/m-p/5851817

Ph Vouters
Valued Contributor

Re: Setting up net-snmp or snmp on HP-UX 11.31 to connect to Whats Up Gold

Dear Troy,

At first glance you ought to address yourself to NET-SNMP using the TCP/IP protocol and not the UDP/IP protocol. So a good command on both the HP-UX and Red Hat systems would be
'netstat -an | grep 161' and notice which of the TCP or UDP IP protocols NET-SNMP uses on both.

Second, I am fully aware of an existing firewall on any Linux but I am not aware of any HP supported firewall burnt into HP-UX. Can you make sure this assumption from me is valid in your case ?

To exhaust the possibilities, can you execute snmpget on your HP-UX server ? Refer to man 1 snmpget on your Linux system for the correct command. You may use -v1 which should use the UDP/IP protocol and -v3 which should use the TCP/IP protocol.

 

As a last idea from me, it would consist into running some network packet sniffer on the NET-SNMP requestor and both the Red Hat and HP-UX systems to pinpoint the difference between the two systems.

 

In the hope this can help you.

TroyBlang
Occasional Advisor

Re: Setting up net-snmp or snmp on HP-UX 11.31 to connect to Whats Up Gold

Hi Ph Vouters

 

I tried the snmpget command and it came back with Timeout No Response from the Windows server.  I see that in my /etc/services I am using the udp for port 161.  Hopefully we can figure out what might be the problem.

TroyBlang
Occasional Advisor

Re: Setting up net-snmp or snmp on HP-UX 11.31 to connect to Whats Up Gold

Hi Ph Vouters

 

I think I know why I am getting the timeout response but I do not know how to fix it.  I have two lan cards lan0 with a ip address and lan1 with an ip address.  So I have two ip addresses for this server.  Could that be the problem?  Let me know.

 

Thanks

Troy

Matti_Kurkela
Honored Contributor

Re: Setting up net-snmp or snmp on HP-UX 11.31 to connect to Whats Up Gold

If the two NICs with different IP addresses are both plugged into the same network segment, that may definitely cause problems. Specifically, it is likely to cause asymmetric routing unless carefully managed, and some network devices (firewalls, switches with address hijacking protection) won't like that at all.

 

You should read this excellent document written by Olivier S. Massé:

http://mayoxide.com/presentations/Understanding_hpux_routing.pdf

Pay particular attention to pages 10-15.

 

The more common way to have a single host use more than one IP address in the same network segment is to use IP aliases. You'd configure one of the IP addresses as usual, e.g. to lan0. The other address would go to "lan0:1" using the same physical NIC.

 

If you need more bandwidth than a single NIC can provide, you'll need APA: in cooperation with a switch that supports the appropriate protocols, it can merge two or more physical NICs into a single virtual entity. For example, lan0 and lan1 could be merged into lan900, which could then be used like a regular NIC, including setting up IP aliases on it.

MK
Matti_Kurkela
Honored Contributor

Re: Setting up net-snmp or snmp on HP-UX 11.31 to connect to Whats Up Gold

@Ph Vouters:

 

> So a good command on both the HP-UX and Red Hat systems would be
> 'netstat -an | grep 161' and notice which of the TCP or UDP IP protocols NET-SNMP uses on both.

 

Since one of the main design requirements of SNMP was simplicity, UDP was originally chosen as the transport protocol for SNMP. This allows SNMP to be used even by tiny microcontrollers without the need to implement a complete TCP state machine. The STD 62 document collection (that is, the current standard definition of SNMP) includes a list of standard transports in RFC 3417; it does not include TCP, but allows transports to be added later.

 

The definition of SNMP over TCP is found in RFC 3430, which is categorised as Experimental.

 

Net-SNMP can indeed use SNMP over TCP if explicitly configured to do so... but not all other SNMP software can. By default, Net-SNMP uses UDP only. I could not quickly find any indication whether or not the Whats Up Gold product supports SNMP over TCP, although it apparently can monitor the availability of other TCP-based services.

 

Whenever a standard port number has been requested, it has been the policy of IANA (Internet Assigned Numbers Authority) to assign the same protocol number for both TCP and UDP, regardless of which transport is actually used by the protocol being standardized. The /etc/services in most Unix-like systems is just a (possibly old) copy of the IANA master list, with possibly some vendor-specific and/or local additions.

 

The IANA master list can be found here:

http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml

 

> I am not aware of any HP supported firewall burnt into HP-UX.

Please see:

https://h20392.www2.hp.com/portal/swdepot/displayProductInfo.do?productNumber=B9901AA

 

Newer HP-UX releases may even include it by default, depending on the choice of OE and options selected at installation time. (I think it will be installed if you choose one of the more severe security hardening options, at least.)

 

MK