# What is a gre0 interface??

## NiceGuy

Hello all,

Just kinda wondering if someone could explain what a gre0 interface is.

Whenever I do a /sbin/ifconfig -a  .. I get along with my expected interfacecs (eth0, eth1 ... etc) a gre0 interface..

```

gre0      Link encap:UNSPEC  HWaddr 

             00-00-00-00-FF-00-00-00-00-00-00-00-00-00-00-00

```

Could someone elaborate on what this "gre0" is .. and why it shows up??

Thanks

Take Care

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## Earthwings

Are you using some kind of vpn software? GRE is the Generic Routing Encapsulation Protocol used for vpn connections.

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