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benniehanas_239
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Jun 05, 2017

sflow NAT vs local subnet to reach MGMT station on another subnet...

Hello I have a question on sflow routing. I can reach my MGMT station from my F5's self-ip, but cannot receive any data from F5, I believe because the hosts are not on the same subnet. I am thinking of either NATting the MGMT station (OpManager) on my Nexus switch, or just moving the MGMT station over from an office to our datacenter. The physical move will be more trouble as all SNMP devices will need to be reconfiged compared to just 2 9k's.

 

Has anyone else needed set up sflow, and what was the final topology? So far I see sflow will fail unless the both F5 and sflow collector hosts appear on the same subnet.

 

4 Replies

  • the sflow destination (or any other logging dst) just needs to be routable from BIG-IP. If you want to use NAT so the dest is locally connected, that'll work as well.

     

  • Thanks Jason,

     

    So I added the route and my F5 comes up in my MGMT station for sflow data. The only prob is, per documentation, it should use it's self IP address from the static route to reach the dest. My prob is it is using another self-ip not tied to the static route I just made which FINALLY got sflow data to my MGMT station.

     

    I don't know why the static route is working to get me data, but my MGMT station shows the source of the sflow data coming from another interface on the F5??? The problem is, now I have two F5 devices now showing up in my MGMT station device list for SNMP managed devices. Is there a way to force the source in the IP header to read the correct interface which would be tied to the new static route?

     

  • this whole sflow config is weird compared to netflow I've configured across multiple other non-F5 devices.

     

  • So I went into CLI and still cannot find why the F5 is sourcing an interface that is not in the path to the sflow receiver:

     

    sys sflow global-settings http { description none poll-interval 10 sampling-rate 1024 } sys sflow global-settings interface { description none poll-interval 10 } sys sflow global-settings system { description none poll-interval 10 } sys sflow global-settings vlan { description none poll-interval 10 sampling-rate 2048 } sys sflow receiver OpManager { address 10.10.10.16 app-service none description none max-datagram-size 1400 partition Common port sflow state enabled