Transfer files over an Ethernet patch cable

Technical note: transfer files over an ethernet patch cable

2026-08-29

2026-08-30

It's possible to just connect two computers together with Ethernet and do a bit of IP configuration:

# On sender ... ip address add dev eth0 fd42:dead:beef::1/48 ip link set dev eth0 up # On receiver ... ip address add dev eth0 fd42:dead:beef::2/48 ip link set dev eth0 up

After a few seconds, pings should work:

# On receiver ... / # ping fd42:dead:beef::1 64 bytes from fd42:dead:beef::1: icmp_seq=1 ttl=64 time=0.649 ms 64 bytes from fd42:dead:beef::1: icmp_seq=2 ttl=64 time=0.376 ms 64 bytes from fd42:dead:beef::1: icmp_seq=3 ttl=64 time=0.414 ms 64 bytes from fd42:dead:beef::1: icmp_seq=4 ttl=64 time=0.340 ms

... and so should this:

# On receiver ... socat - TCP6-LISTEN: 1234 | dd status = progress > big_file.tar.gz # On sender ... socat - 'TCP6-CONNECT: [fd42:dead:beef::2] : 1234 ' < big_file.tar.gz

These commands assume you are using Linux, but this trick works everywhere.

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