Tendermint: What is the meaning of "Cannot add non-routable address"

[srmo]

After having troubles with pex in 0.15 release, I've resorted to 0.12 where I now see
Cannot add non-routable address 192.168.55.xx.
It's a simple VirtualBox setup with 3 debian VMs.
Each node reports the other 2 nodes as non-routable.
Each node is configured to have the other 2 nodes as seed.

What is the meaning of that? Is that a problem? What to do about it?

2018-02-15_21:42:15.75976 E[02-15|21:42:15.759] Cannot add non-routable address 192.168.55.11:46656 module=p2p book=/etc/tendermint/node/addrbook.json 2018-02-15_21:42:15.75977 E[02-15|21:42:15.759] Cannot add non-routable address 192.168.55.12:46656 module=p2p book=/etc/tendermint/node/addrbook.json

[melekes]

https://github.com/tendermint/tendermint/blob/develop/p2p/netaddress.go#L189

I think this code was just copied from btcd. Means before adding an address to addrbook, we check if it's routable.

You can turn off strict routability by setting addr_book_strict to false.

[p2p]
addr_book_strict=false

[ebuchman]

You should also be able to get around it by adding them to private_peer_ids if you're using a recent enough version