sFlow

If you are running an HPE Aruba (formally ProCurve) switch you may come across cases where your switch (in the example above a 5400R zl2) has multiple IP Addresses/VLANs and you need it to talk to another service (in my case syslog and sFlow receivers) on a set interface.

When this occurs you can use the ip source-interface command (make sure you are in config mode first) to define the IP Address or VLAN that you want the switch to talk out on. In my case VLAN2 which is used as the management network for the network switches (VLAN1 being the default network that switches use if multiple addresses are configured).

sFlow - Top TalkersPRTG is by far my favoured tool for monitoring IT infrastructure. With its built in sensors you can check the PING time for a server, check that windows services are up and running or with a little tweaking monitor paper trays in a MFP (and so much more).

A recently discovered feature for me is the sFlow monitor. This tracks in near real time the flow of different types of data (e.g. SMTP/HTTP/FTP/DNS lookups) that flow through network infrastructure.

In my case the entire network is built on HP ProCurve layer 2/3 switches which makes for pretty easy setup.

To follow this guide you will need

  • The IP address of your PRTG server (in my case 172.16.8.27)
  • Admin access to your PRTG console and a ‘device’ setup for your switch
  • Admin access to your switches through Telnet/SSH (I use PuTTY to administer my switches through Telnet)
  • 5 minutes

So now that I have all of this extra info what am I to do with it? Well with the sFlow sensor setup you can…

  • See if your network infrastructure is experiencing bottlenecks…
  • …and if so where the bottleneck is and what kind of data is causing it (e.g. large file transfers)…
  • …and see what clients are causing it.
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