grml-vpn

We just have a developer meeting in Graz and Gebi wrote a script namend grml-vpn. grml-vpn is a program to establish encrypted communication channels in a network. We just tested it and it really rocks. :-) It's very easy to use, take a look at the usage example:

Gebi (root@gebi) starts grml-vpn on his laptop with key/passphrase 'test' and uses his and my ip for the encrypted communication channel:

root@gebi # grml-vpn -k test add 1000 192.168.1.104 192.168.1.101

I (root@mika) am using the same command line on my laptop:

root@mika # grml-vpn -k test add 1000 192.168.1.104 192.168.1.101

To demonstrate that it's working let's use IPsec's setkey command:

root@mika # setkey -D
192.168.1.101 192.168.1.104
        esp mode=transport spi=1000(0x000003e8) reqid=0(0x00000000)
        E: aes-cbc  d8e8fca2 dc0f896f d7cb4cb0 031ba249
        seq=0x00000000 replay=0 flags=0x00000000 state=mature
        created: Sep 22 15:15:02 2005   current: Sep 22 15:19:40 2005
        diff: 278(s)    hard: 0(s)      soft: 0(s)
        last: Sep 22 15:15:14 2005      hard: 0(s)      soft: 0(s)
        current: 1488(bytes)    hard: 0(bytes)  soft: 0(bytes)
        allocated: 12   hard: 0 soft: 0
        sadb_seq=1 pid=20148 refcnt=0
192.168.1.104 192.168.1.101
        esp mode=transport spi=1001(0x000003e9) reqid=0(0x00000000)
        E: aes-cbc  d8e8fca2 dc0f896f d7cb4cb0 031ba249
        seq=0x00000000 replay=0 flags=0x00000000 state=mature
        created: Sep 22 15:15:02 2005   current: Sep 22 15:19:40 2005
        diff: 278(s)    hard: 0(s)      soft: 0(s)
        last: Sep 22 15:15:14 2005      hard: 0(s)      soft: 0(s)
        current: 768(bytes)     hard: 0(bytes)  soft: 0(bytes)
        allocated: 12   hard: 0 soft: 0
        sadb_seq=0 pid=20148 refcnt=0

Now let's check whether it's really encrypted:

root@mika # ping 192.168.1.104
[...]
root@gebi # tcpdump
15:16:26.066885 IP 192.168.1.101 > 192.168.1.104: ESP(spi=0x000003e8, seq=0xa)
15:16:26.067040 IP 192.168.1.104 > 192.168.1.101: ESP(spi=0x000003e9, seq=0xa)

Bingo! :-)