While checking interface statistics on a Cisco 3845, I noticed the following layer 3 interfaces.
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 126.96.36.199 YES NVRAM up up
GigabitEthernet0/1 10.10.10.1 YES NVRAM up up
GigabitEthernet0/0/0 unassigned YES NVRAM administratively down down
SSLVPN-VIF0 unassigned NO unset up up
Tunnel0 192.168.255.2 YES NVRAM up up
I can explain all interfaces, except the SSLVPN-VIF0 interface. I tried to look at the internet, but that didn’t result in any useful information. I used Cisco’s Output Interpreter, but that didn’t help either.
INFO: The following interfaces show the interface configuration ‘method’ as ‘unset’. SSLVPN-VIFO This means that no configuration changes were made to the interface since the last reload.
I noticed the same interface on a Cisco 1811 router, but not on the Cisco 871 and Cisco 878 routers. The interface cannot be related to SSL VPN functionalities, because that feature isn’t configured on the routers. At least that was what I thought at first. I checked my home router, because it has SSL VPN configured and found that the SSLVPN-VIF0. As the abbreviation implies, SSLVPN-VIF0 stands for “SSLVPN Virtual Interface 0”.
An IP address is assigned to the interface, after establishing a SSLVPN connection. You can retrieve more information about the SSLVPN-VIF interface by using multiple show interface SSLVPN-VIF commands. An example is shown below:
router#show interface SSLVPN-VIF 0 switching
SSLVPN-VIF0 ***Internally created by SSLVPN context home***
Switching path Pkts In Chars In Pkts Out Chars Out
Process 26 2657 4 240
Cache misses 0 – – –
Fast 0 0 0 0
Auton/SSE 0 0 0 0
NOTE: all counts are cumulative and reset only after a reload.
So don’t panic when you see the SSLVPN-VIF0 interface on your router. You now know where it is coming from.