Okay, this code has always been a little tough to follow. Rough history: 1. Magic loopback address was introduced (presumably so that 127.0.0.1 would never be returned, this is _probably_ wrong) 2. Only one local IP was returned, causing some applications to do the wrong thing if it's the wrong one 3. All local IPs returned, being sorted by routing metric. Magic loopback address used as fallback to preserve behavior. 4. Improved support for other networking features added (actual route information, etc.) 5. Adding the _local_ routes means that the "return local IPs by route metric" routine adds the loopback IPs to the list (this is definitely wrong) So, the proposed patch here removes these loopback IPs (and ones that aren't found in the routing list) from the list of returned addresses. This appears to me to be correct. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10825#note_139067