Why can't packets get back to the bridge?

[mauricev]

Using OS X (1.6.8) with L2TP to create a remote VPN tunnel under Linux, I have first discovered that the connection requires SecureNAT and DHCP. Without either, OS X fails to even consider negotiating a connection. That is, SoftEther seems to just ignore it.

With a connection in place, SoftEther does assign both a MAC and an IP (from its DHCP). The remote OS X client can sent ping packets to the Linux VPN server. They cross the bridge and do reach the target (also OS X). It responds with a ping packet, but this packet never gets back to the real interface the bridge is assigned to. The target OS X system has the assigned MAC in its arp table, but oddly, the Linux server does not.

[mauricev]

I am an idiot. My SoftEther is running under VMWare and it had to be configured (in two places) to allow promiscuous mode.