Windows Version

Microsoft Windows [Version 10.0.26200.9711]

WSL Version

2.7.3.0

Are you using WSL 1, WSL 2, or WSLC?

• WSL 2
• WSL 1
• WSLC

Kernel Version

No response

Distro Version

No response

Other Software

No response

Repro Steps

1. Enable a Windows HTTP proxy with bypass entries such as localhost;127.*;10.*;192.168.* (included in Clash Verge Rev's Windows defaults).

2. Enable these settings in .wslconfig:

   [wsl2]
   networkingMode=mirrored
   autoProxy=true

3. Once those settings are active, open a fresh WSL session and inspect no_proxy / NO_PROXY. The imported list contains 127.*.

4. Start a local server in WSL:

   python3 -m http.server 18080 --bind 127.0.0.1

5. In a second fresh WSL session, compare the imported bypass list with a CIDR override, keeping the proxy enabled:

   printf 'no_proxy=%s\nNO_PROXY=%s\n' "$no_proxy" "$NO_PROXY"
   
   # loopback get proxied unexpectedly
   curl -q -v --max-time 5 http://127.0.0.1:18080/ -o /dev/null
   # We need to set no_proxy manually to make loopback not being proxied 
   no_proxy=127.0.0.0/8 NO_PROXY=127.0.0.0/8 \
   curl -q -v --max-time 5 http://127.0.0.1:18080/ -o /dev/null

Expected Behavior

Windows IP-range bypass rules should retain their meaning for Linux clients such as curl after import.

Suggested minimal fix: normalize unambiguous numeric IPv4 prefix wildcards when building ProxyBypassesComma, preserving the original ProxyBypasses entries:

127.*       -> 127.0.0.0/8
10.*        -> 10.0.0.0/8
192.168.*   -> 192.168.0.0/16
172.16.*    -> 172.16.0.0/16

Leave other patterns unchanged. This improves compatibility for CIDR-capable clients such as curl.

Precedent: hyper-util PR #309 implements the same normalization when importing WinINET proxy exclusions, fixing hyper #4128.

Actual Behavior

WSL changes the separators but exports the wildcard entries unchanged:

Windows ProxyOverride: localhost;127.*;10.*;192.168.*
WSL NO_PROXY/no_proxy: localhost,127.*,10.*,192.168.*

IP wildcards are valid Windows native proxy bypass notation, but not well-supported in Linux (e.g., curl's NO_PROXY parser does not interpret 127.* as an IP range).

The first request connects through the proxy; the second request (i.e., CIDR override) connects directly.
Without CIDR override, local or private API requests can consequently fail with 502 or connection errors, depending on the proxy.

Relevant source (WSL 2.7.3):

• LxssHttpProxy.cpp:109–120: copies WinHTTP bypass entries through encoding conversion and joins them into ProxyBypassesComma; no wildcard normalization.
• LxssUserSession.cpp:4078–4081: exports that string directly to both no_proxy and NO_PROXY.

Diagnostic Logs

No response