Why can't packets get back to the bridge?
Posted: Thu Feb 13, 2014 6:49 am
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.
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.