setting the other end's TCP segment size

[Giorgos Keramidas]

On Wed, 30 Jul 2008 00:09:45 -0700, perryh at pluto.rain.com wrote:
>>>> Is there a simple way for a FreeBSD system to cause its peer to
>>>> use a transmit segment size of, say, 640 bytes -- so that the peer
>>>> will never try to send a packet larger than that?
>>>>
>>>> I'm trying to get around a network packet-size problem.  In case
>>>> it matters, the other end is SunOS 4.1.1 on a sun3, and I've been
>>>> unable to find a way to limit its packet size directly.
>>>
>>> Setting the interface MTU should do it, i.e.:
>>>
>>>     ifconfig re0 mtu 640
>>>
>>> Not all interfaces support setting the MTU and some may have range
>>> restrictions though.
>>
>> In particular, this seems to work with my wlan0 interface, but not
>> with my re0 interface ...
>
> That's certainly simple enough, and xl0 apparently supports the
> reduced mtu setting.  It seems to be working just fine.  Thanks!
>
> I'd thought of trying to set the sun's MTU, but hadn't been able
> to find a way to do it.  It had never occurred to me that setting
> the *recipient's* MTU would limit the *sender's* packet size.

You can edit `/etc/hostname.foo0' in the Sun too, and add something
like:

    192.168.1.10/24 mtu 640

but since now you are happy with the new setup, that's fine :)