看來該跑 FreeBSD 5.4 了..

剛剛翻 FreeBSD/i386 5.4-RELEASE Release Notes , 看到這幾條 :

Ethernet flow control is now disabled by default in the fxp(4) driver, to prevent problems with a system panics or is left in the kernel debugger.

這個好像是要解決我之前在 IP 被衝就 Hang 住!? 講的那個問題!?

The ipfw(8) ipfw fwd rule now supports the full packet destination manipulation when the kernel option options IPFIREWALL_FORWARD_EXTENDED is specified in addition to options IPFIREWALL_FORWARD. This kernel option disables all restrictions to ensure proper behavior for locally generated packets and allows redirection of packets destined to locally configured IP addresses. Note that ipfw(8) rules have to be carefully crafted to make sure that things like PMTU discovery do not break.

這個就不是很清楚了, 不過我們某台 Proxy ( FreeBSD 5.3 ) 使用 ipfw fwd 上面有很大的問題.

升成 5.4 看看好了.. orz