Configure Health Monitor for Netbios Name Server UDP/137 on F5 big-ip

Hi Francisco,

 

 

I think you could continue using the UDP monitor if that's successfully checking when the service is up. However, if you're using a default UDP monitor with no send string, I don't think it's a good check of whether the service is up. You could try using nmblookup (http://linux.die.net/man/1/nmblookup) to test to a WINS server, record the request string and try configuring that as the UDP monitor send string. For the receive string, you'd want to look for something that only occurs in successful responses.

 

 

You could then combine the UDP monitor with an ICMP monitor together. The UDP monitor expects to receive an ICMP port unreachable response from the server if the UDP service is down. So you can use an ICMP monitor to ensure that the pool member is still marked down if the server is down and not sending the ICMP service unavailable message.

 

 

If you can't get the UDP monitor working for this, you could search for a Perl library that supports querying WINS servers and use that in an external monitor. Or you could copy nmblookup to LTM and use that in an external monitor. The latter option wouldn't be supported by F5, but could work.

 

 

For example external monitors, you can check the Codeshare:

 

 

http://devcentral.f5.com/wiki/default.aspx/AdvDesignConfig/codeshare

 

http://devcentral.f5.com/wiki/default.aspx/AdvDesignConfig/TemplateForExternalLtmMonitors.html

 

 

Aaron