Send DHT queries to “router.bittorrent.com” response garbled text

Question

I read the DHT Protocol in bep_0005 page.

But when I send a ping query or a find_node query, the server response a garbled text (both of router.bittorrent.com:6881

Answer 1

the server response a garbled text

No, the response is bencoded and contains raw binary data.
It CAN NOT be treated as text.

In BEP5, to make the raw binary node_id in the examples printable, it has cleverly been chosen to consist of only alphanumeric characters.
See:
Bittorrent KRPC - Why are node ID's half the size of an info_hash and use every character a-z?

The ip key is a extension explained in: BEP42 - DHT Security extension

The received response is fully valid.

TODO: Working Java code