net.inet.ip.forwarding and net.inet.ip.fastforwarding

[eculp at bafirst.com]

Quoting Sam Leffler <sam at errno.com>:

> Matt Emmerton wrote:
>>> Hi guys.
>>>
>>> What's the difference between net.inet.ip.forwarding and
>>
>> net.inet.ip.fastforwarding  ?
>>
>>> What's the role of net.inet.ip.fastforwarding ?
>>
>>
>>> From inet(4):
>>
>>      IPCTL_FORWARDING      (ip.forwarding) Boolean: enable/disable
>> forwarding
>>                            of IP packets.  Defaults to off.
>>
>>      IPCTL_FASTFORWARDING  (ip.fastforwarding) Boolean: enable/disable the
>> use
>>                            of fast IP forwarding code.  Defaults to off.
>> When
>>                            fast forwarding is enabled, IP packets are for-
>>                            warded directly to the appropriate network inter-
>>                            face with a minimal validity checking, which
>>                            greatly improves the throughput.  On the other
>>                            hand, they bypass the standard procedures, such
>> as
>>                            IP option processing and ipfirewall(4) checking.
>>                            It is not guaranteed that every packet will be
>>                            fast-forwarded.
>>
>
> This quote is out of date; on current fastforwarding is purely an 
> optimization path--if the packet requires features not supported by 
> the fast path then it's processed normally.

Maybe I should have another ristreto before asking this, but based on 
what I understand from this thread and speaking of current 7.0:

  a. I would set both in sysctl.conf
     net.inet.ip.forwarding=1
     net.inet.ip.fastforwarding=1
  b. There would be no "down side" in current 7.0

Is this more or less correct?  If so, will this posibly be the case in 
the 6.0 release also or only in current?

Thanks,

ed