It appears that pegging 'ce' NIC's to 100fdx by setting ndd in a startup script can cause probs. (And I think the system method is similarly flawed)
SUN recommended method of nic pegging is now to use the /platform/sun4u/kernel/drv/ce.conf file
See http://sunportal.sunmanagers.org/pipermail/summaries/2003-December/004761.html
put this in /platform/sun4u/kernel/drv/ce.conf
adv_autoneg_cap=0 adv_10hdx_cap=0 adv_10fdx=0 adv_100hdx_cap=0 adv_100fdx_cap=1 adv_1000hdx_cap=0 adv_1000fdx_cap=0 adv_100T4_cap=0;
To use these interfaces with PNM you need to add the below 2 lines to /etc/system:
set ce:ce_reclaim_pending=1 set ce:ce_taskq_disable=1