Jumbo frames on Solaris

For e1000g (Solaris):
Change /kernel/drv/e1000g.conf to:

# 0 is for normal ethernet frames.
# 1 is for upto 4k size frames.
# 2 is for upto 8k size frames.
# 3 is for upto 16k size frames.
# These are maximum frame limits, not the actual ethernet frame
# size. Your actual ethernet frame size would be determined by
# protocol stack configuration (please refer to ndd command man pages)
# For Jumbo Frame Support (9k ethernet packet)
# use 3 (upto 16k size frames)

For rge (Solaris):
Maximum MTU supported by rge is 7000.
Change /kernel/drv/rge.conf to:

default_mtu = 7000;

Then reboot.

The result:

xeon# ifconfig -a
. . .
e1000g1: flags=201000843 mtu 9000 index 2
inet netmask ffffff00 broadcast
ether 0:18:f3:ef:2a:d1