> > Is there a way to change the MTU on the le0 interface??
>
> You should be able to lower it (e.g. ifconfig le0 mtu 512) but not increase
> it over 1500.

from ifconfig man page:

mtu n           Set the maximum transmission unit of the interface to n.
                Most interfaces don't support this option.

from the shell:

nino kupa:/home/nino > sudo ifconfig -a
Password:
le0: flags=8b63<UP,BROADCAST,NOTRAILERS,RUNNING,PROMISC,ALLMULTI,SIMPLEX,MULTICAST>
mtu 1500
        address: 08:00:2b:bc:d6:c4
        media: Ethernet manual
        status: active
        inet 192.168.100.5 netmask 0xffffff00 broadcast 192.168.100.255
lo0: flags=8009<UP,LOOPBACK,MULTICAST> mtu 33200
        inet 127.0.0.1 netmask 0xff000000
ppp0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
ppp1: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
ppp2: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
ppp3: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
sl0: flags=c010<POINTOPOINT,LINK2,MULTICAST> mtu 296
sl1: flags=c010<POINTOPOINT,LINK2,MULTICAST> mtu 296
sl2: flags=c010<POINTOPOINT,LINK2,MULTICAST> mtu 296
sl3: flags=c010<POINTOPOINT,LINK2,MULTICAST> mtu 296
nino kupa:/home/nino > sudo ifconfig le0 mtu 512
ifconfig: SIOCSIFMTU: Invalid argument
nino kupa:/home/nino >

Any (other? :-) suggestions?

--Nino