[c-nsp] Mac Incompatibility with PPPoE?

[Patrick Bohannon]

Longshot here I know, but we're terminating SBC DSL on a 7204 VXR and using
PPPoE for IP assignment, etc.  Clients using Windows-based PCs either
directly connected to the DSL CPE or behind a router have no trouble
whatsoever accessing the gateway and beyond.  To be more specific, in the
case of either a 3rd-party router (pretty much any vendor) or Windows itself
doing the PPPoE negotiation, there is no trouble.

Clients using Macintosh OS X (many variants) can only ping to the gateway
(the 7204 VXR loopback interface) but not beyond.

More notes:

* If I replace the Macintosh with a Windows-based PC on the _same DSL line_,
using the _same IP address_, I can traffic to the Internet without a
problem.  It's not line-specific.

* I have manually set the MTU to 1492 using ifconfig in OS X.

Has anyone see similar behavior, or have any suggestions for troubleshooting
techniques?  Some of the relevant config is below:

Thanks!

interface Virtual-Template1
 mtu 1492
 ip unnumbered Loopback5
 ip route-cache policy
 ip route-cache flow
 no ip route-cache cef
 peer default ip address pool sbc_bton_pool
 ppp authentication pap 
 ppp chap refuse
 ppp ipcp dns x.x.x.x x.x.x.x