Freebsd IP Forwarding performance (question, and some info) [7-stable, current, em, smp]

[Steve Bertrand]

Mike Tancsa wrote:
> At 04:04 AM 6/29/2008, Paul wrote:
>> This is just a question but who can get more than 400k pps forwarding 
>> performance ?
> 
> 
> OK, I setup 2 boxes on either end of a RELENG_7 box from about May 7th 
> just now, to see with 2 boxes blasting across it how it would work.  
> *However*, this is with no firewall loaded and, I must enable ip fast 
> forwarding. Without that enabled, the box just falls over.
> 
> even at 20Kpps, I start seeing all sorts of messages spewing to route -n 
> monitor
> 
> 
> got message of size 96 on Mon Jun 30 15:39:10 2008
> RTM_MISS: Lookup failed on this address: len 96, pid: 0, seq 0, errno 0, 
> flags:<DONE>
> locks:  inits:
> sockaddrs: <DST>
>  default

Mike,

Is the monitor running on the 7.0 box in the middle you are testing?

I set up the same configuration, and even with almost no load (< 1Kpps) 
can replicate these error messages by making the remote IP address (in 
your case 'default', disappear (ie: unplug the cable, DDoS etc).

...to further, I can even replicate the problem at a single packet per 
second by trying to ping an IP address that I know for fact that the 
router can not get to.

Do you see these error messages if you set up a loopback address with an 
IP on the router, and effectively chop your test environment in half? In 
your case, can the router in the middle actually get to a default 
gateway for external addresses (when I perform the test, your 'default' 
is substituted with the IP I am trying to reach, so I am only assuming 
that 'default' is implying default gateway).

Steve