As a follow up to legacy/trac#12971, our SOCKS5 code can now send back specific errors in response to requests fairly easily. A quick glance through the code suggests that the following cases (at a minimum) should be changed to do the right thing: * Invalid/malformed address (`SOCKS5_ADDRESS_TYPE_NOT_SUPPORTED`, `SOCKS5_GENERAL_ERROR`, `SOCKS5_NOT_ALLOWED` depending on the case) * CONNECT command while SafeSocks is set to an IP address (`SOCKS5_NOT_ALLOWED`) One could argue that legacy/trac#11138 would magically fix these things as well, but since returning errors is a one line addition (and the unit tests) per case, there's no reason not to make the changes now.