I need an explanation of what exactly the 'link encap' field returned by ifconfig means in relationship to an interface. Information about how to change it and where it comes from would be a tremendous help. This is apparently a kernel-level feature of a network interface that can be viewed with ifconfig. How can it be changed? The specific problem I am trying to work through is related to openvpn over TUN devices. One end of the tunnel reports 'Link Encap:point-to-point ' and the other says 'Link encap:UNSPEC'. There seems to be no list specifically for discussion of tun devices, and I have seen numerous unanswered postings about various configurations that include the 'unspecified encapsulation' information. ifconfig does no appear to be able manipulate the encapsulation attribute. Exhibit A- tun0 Link encap:Point-to-Point Protocol inet addr:10.1.0.2 P-t-P:10.1.0.1 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1255 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:10 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) Exhibit B- tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:10.1.0.1 P-t-P:10.1.0.2 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1255 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:10 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) - : send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html