socks4a proxy type

[ilf@…]

Currently, supported Proxy types are HTTP, SOCKS4 and SOCKS5. Tor recommends using SOCKS4a, which is not supported.

[wilmer]

pony means this will only happen if someone else claims the bug, sorry.

Any pointer on the recommendation? Why does it really matter, and is 4a very different from plain 4?

[anonymous]

Applications that do DNS resolves themselves may leak information. Consider using Socks4A (e.g. via Polipo or socat) instead.

There are 3 versions of SOCKS you are likely to run into: SOCKS 4 (which only uses IP addresses), SOCKS 5 (which usually uses IP addresses in practice), and SOCKS 4a (which uses hostnames).

​https://trac.torproject.org/projects/tor/wiki/doc/TorFAQ#IkeepseeingthesewarningsaboutSOCKSandDNSandinformationleaks.ShouldIworry

A server using protocol SOCKS4A must check the DSTIP in the request packet. If it represents address 0.0.0.x with nonzero x, the server must read in the domain name that the client sends in the packet. The server should resolve the domain name and make connection to the destination host if it can

​https://en.wikipedia.org/wiki/SOCKS#SOCKS4a

[dx]

Implemented in ​https://github.com/bitlbee/bitlbee/commit/12f041de930a20a3df91f9f90c4fd518162ea82c

Quoting commit log:

This is slightly pointless for the suggested use case (tor), since with socks5 we already send a hostname instead of an IP address.

Either way, it was easy to implement, so I hope it helps.