Any arp table size limitations?

Lowell Gilbert freebsd-questions-local at
Wed May 29 22:51:27 UTC 2013

Peter Andreev <andreev.peter at> writes:

> We are connecting to an IXP, they have tested our FreeBSD 9.1 server and
> said we can store only about 600 MACs simultaneously. So I'd like to ask if
> there is any arp table size limitations and if so, how we can increase the
> limit?

I looked at the code and there don't seem to be any arbitrary
limits. The code isn't optimized for really large numbers of entries,
but 600 isn't what I'd consider large in this context.

I ran a simple shell script and had no problems entering many thousands
of static ARP entries, so my interpretation from reading the code isn't
horribly wrong. I think you need to find out what kind of problems they
ran into at 600 entries. 

As a (maybe-irrelevant) side point, I don't know what you mean by IXP,
since in my background the term means "Internet eXchange Point," and
isn't likely to get anywhere close to 600 ARP entries on a single

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