topic Re: HP ProCurve Switch 2650 - ARP not Working in Switches, Hubs, and Modems

HP ProCurve Switch 2650 - ARP not Working

Justin Selleck — Fri, 14 Sep 2007 09:09:47 GMT

Today I noticed that all of my ports on the HP seem to be getting the same amount of traffic. Upon further investigation I found that there were only 2 arp entries so I am assuming that the traffic is all broadcast traffic. Do you have any ideas why arp would not be caching? Thanks for any help!!

Here is my config:

; J4899A Configuration Editor; Created on release #H.07.02

hostname "HP ProCurve Switch 2650"
snmp-server contact "Smooth Fusion Operations Team"
snmp-server location "The Planet - Dallas, TX"
cdp run
ip default-gateway XX.XX.199.3
snmp-server community "sfpublic" Operator
vlan 1
name "Optional"
untagged 1-46,49-50
ip address XX.XX.199.18 255.255.255.0
no untagged 47-48
exit
vlan 4
name "Eth5"
untagged 47-48
exit
password manager
password operator

Re: HP ProCurve Switch 2650 - ARP not Working

Mohieddin Kharnoub — Fri, 14 Sep 2007 13:52:22 GMT

Hi

Usually Spanning Tree topology changes will flush the arp and clear it upon building a new topology, so i suggest you check for any loops in your network.

One more thing, you have an (ancient) firmware and i suggest you enjoy the free firmware update that made alot of changes and major enhancements to this well known product.

Check this here:
http://www.hp.com/rnd/software/j49001038.htm

And maybe after updating to the new firmware your issue will be resolved.

Note: i saw that you are using CDP, and i think this won't run after updating to the new firmware, and you can use the LLDP instead.

Good Luck !!!

Re: HP ProCurve Switch 2650 - ARP not Working

Justin Selleck — Fri, 14 Sep 2007 14:58:14 GMT

I have upgraded the firmware on another 2650 we have. I'll be installing and checking for loops monday.

Thanks!

Re: HP ProCurve Switch 2650 - ARP not Working

Justin Selleck — Fri, 14 Sep 2007 14:59:41 GMT

I have upgraded the firmware on another 2650 that we have locally. I'll be installing and checking for loops monday.

We were not using CDP so that should not be a problem.

I'll let you know if the problem gets resolved.

Thanks!

-Justin

Re: HP ProCurve Switch 2650 - ARP not Working

Thomas Joebstl — Fri, 14 Sep 2007 15:10:39 GMT

I dont see that ip routing is enabled so the arp cache on the 2650 is quite irrelevant.
The arp cache is only used when some station accesses the switch or vice versa. Spanning tree seems to be disabled as well so it wont cause any arp flushes.
Normal switching operation uses the mac table/cache which is something different (use show mac-address to display that).
You can check if it's mostly broadcast by looking at the port counters, there are different counters for uni/broad/multicast packets.
And even if it is broadcast traffic the arp/mac cache wont help anything - broadcasts are by definition broadcastet, i.e. flooded out all ports.
Hook up a sniffer (e.g. wireshark) to see which station sends those packets and which type those exactly are.

But as stated above, upgrading the firmware is recommended. Dont forget to read the info in the yellow boxes on the fw download page else you'll run into troubles.