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

RouterOS General
1

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

2

show the output of
ip arp

3

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.

4

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…