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ROS 6.30.1 - ARP table overflow, please consider increasing max-arp-entries.

Posted: Wed Oct 14, 2015 9:56 pm
by blahblah927
My RB1100AHx2 box(ROS 6.30.1) keeping getting message says
ARP table overflow, please consider increasing max-arp-entries.
This box is set up with VLANs on bridge.
arp.png

I tried change IP Settings, Max ARP Entires to 16384 and 32768, both does'nt stop the warning message.
ipsetting.png

however , I have the same setup on a PC box with ROS 5.x at other site. that site doesn't have this problem.

please help me out.

Best Regards

Re: ROS 6.30.1 - ARP table overflow, please consider increasing max-arp-entries.

Posted: Wed Oct 14, 2015 10:53 pm
by sup5
show the output of
ip arp

Re: ROS 6.30.1 - ARP table overflow, please consider increasing max-arp-entries.

Posted: Thu Oct 15, 2015 6:21 am
by blahblah927
show the output of
ip arp
Here is the arp list
arplist.png
and here are the MACs on bridge
bridgehost.png
most time the arp list have 100-300 entries only. so does the bridge.

Re: ROS 6.30.1 - ARP table overflow, please consider increasing max-arp-entries.

Posted: Thu Oct 15, 2015 9:39 am
by dada
Hi,

IMHO the ROS doesn't show incomplete ARP entries (i.e. the cases when ARP query was not replied by remote host or is not considered valid for some other reason like timeout etc) so it is still possible that you have larger network assigned to some interface of the router and some kind of scan is running on the IPs in the subnet.

I would check this:
1) is there larger subnet assigned to an interafce? (/16 or so)
2) do you see large amount of ARP traffic in packet sniffer on that interface?

In other case it may be a bug in ROS which causes problems with ARP or false warnings...