wired PPP problem: ppp connection fail, slow down on FreeBSD but fine on Windows

[张韡武]

在 2006-11-28二的 18:05 +0800，张韡武写道：
> The FreeBSD gateway machine has one end connect to ADSL modem through
> pppoe, the other connects to LAN and act as NAT gateway.
> 
> PPP connection can be established correctly, then after 5 hour or 10
> hour, connection speed become very slow or (more frequently) simply
> cannot connect (a.k.a. browsing web pages time out). Then, ping from LAN
> client hosts to external network would simply timeout, ping from NAT
> gateway to 10.10.10.5 (that's the other end of the PPPOE connection)
> keep getting this message:
>         ping: send to: No buffer space available
> At the same time, top(1) shows 80~95 CPU resource is taken by
> 'interrupt'.
> 
> stop ppp by "/etc/rc.d/ppp stop" and re-start this process usually will
> not get re-connected (/var/log/ppp.log is like 'carrier -> stop ->
> redial', that is we don't reach the step of login). Reboot computer
> usually also do not help. After fighting the problem for an hour or so,
> suddenly it (pppoe) become working again.

I forgot to mention in such case (connection is slow but not completely
broken), top(1) often shows aroudn 20% to 30% CPU resource is taken by
'interrupt', 20% to 30% by ppp and around 50% free. Such situation won't
last long before connection become completely useless.