Community discussions

MikroTik App
 
Hlop
just joined
Topic Author
Posts: 4
Joined: Fri Dec 10, 2010 6:34 pm

ARP table overflow, please consider increasing max-arp-entries

Tue Feb 24, 2015 10:10 am

What it is going on. Server with RouterOS v6.27 every four day it have message in the log "ARP table overflow, please consider increasing max-arp-entries" when it happen CPU was load 100% I look in arp table but see there only 500 mac address, after disable WAN port CPU load 2% and messages "ARP table overflow" in the log does not appear.
 
dada
Member Candidate
Member Candidate
Posts: 245
Joined: Tue Feb 21, 2006 1:44 pm

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

Tue Feb 24, 2015 4:42 pm

if you have large subnet attached to LAN interface than a scan for IPs in the range can cause large amount of ARP entries in ARP table. Most of them will be unresolved ones and ROS doesn't show them ...
 
Hlop
just joined
Topic Author
Posts: 4
Joined: Fri Dec 10, 2010 6:34 pm

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

Tue Feb 24, 2015 5:54 pm

No I doesn't have large subnet attached to LAN interface, only 500 - 600 users and other servers serve 500 - 600 users but doesn't have such problem. Problem have only two servers which connect with same ISP. My ISP gave me subnet /27. On the wan port I see in arp table only mac-address gateway. Have any idea?
 
dada
Member Candidate
Member Candidate
Posts: 245
Joined: Tue Feb 21, 2006 1:44 pm

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

Tue Feb 24, 2015 6:22 pm

and what size of subnets(s) do you have directly connected to non-WAN interfaces?

IMHO it is possible that MT uses 512 limit on ARP table...


It looks like someone other had the same problem already:
http://forum.mikrotik.com/viewtopic.php?f=1&t=92208
 
Hlop
just joined
Topic Author
Posts: 4
Joined: Fri Dec 10, 2010 6:34 pm

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

Tue Feb 24, 2015 6:55 pm

Thanks dada for the link to this topic but I had read this topic already.
ip settings print

ip-forward: yes
send-redirects: yes
accept-source-route: no
accept-redirects: no
secure-redirects: yes
rp-filter: no
tcp-syncookies: no
max-arp-entries: 8192
arp-timeout: 30s
icmp-rate-limit: 10
icmp-rate-mask: 0x1818
allow-fast-path: yes

As you can see max-arp-entries 8192
Server has two interface
ether1 I use it as WAN interface and has ip subnet with /24 mask
ether2 I add 7 VLAN intarfaces
every VLAN has ip subnet with /24 mask
 
dada
Member Candidate
Member Candidate
Posts: 245
Joined: Tue Feb 21, 2006 1:44 pm

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

Tue Feb 24, 2015 7:08 pm

I think you have to create a supot.rif file and ask MT support for a solution...
 
orgtopus
just joined
Posts: 5
Joined: Thu Dec 06, 2012 1:01 am

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

Thu Apr 23, 2015 12:48 pm

CASE : ARP table overflow, please consider increasing max-arp-entries
resolve : /ip settings set max-arp-entries=16384
(16384 = 16Mx1024)
 
User avatar
kikeco
just joined
Posts: 8
Joined: Tue Apr 21, 2015 6:59 pm

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

Sun Mar 20, 2016 7:01 pm

In my case it was The Dude what made this problem to show. Increasing the max ARP entries to 16384 solved the problem.

Who is online

Users browsing this forum: amt, Erbit, jaclaz, lurker888, smirgo, TheCat12 and 103 guests