Problem

When running OpenClaw on a host with Clash Pro (or Surge) in TUN/enhanced mode, all DNS resolutions return fake-ip addresses in the 198.18.0.0/15 range (RFC 2544 Benchmark). The web_fetch tool's SSRF guard blocks these as "private/internal/special-use IP address", making web_fetch completely unusable.

Error: Blocked: resolves to private/internal/special-use IP address

This affects all URLs — not just internal ones — because TUN mode hijacks DNS at the system level.

Environment

• macOS (Apple Silicon)
• ClashX Pro with TUN/enhanced mode enabled
• utun interface bound to 198.18.0.1/16
• All DNS queries return 198.18.x.x fake-ip addresses
• Actual traffic is transparently forwarded to real public IPs via the proxy tunnel

Root Cause

web_fetch uses withStrictGuardedFetchMode() which performs DNS resolution → IP check before connecting. The resolved 198.18.x.x addresses are classified as RFC 2544 special-use and blocked.

The codebase already has allowRfc2544BenchmarkRange logic in resolveIpv4SpecialUseBlockOptions() (~line 6390 in model-selection), and browser.ssrfPolicy supports allowPrivateNetwork. However, web_fetch has no corresponding configuration — it's hardcoded to STRICT mode.

Proposed Solution

Add a configurable SSRF policy for web_fetch (and ideally all tool-level fetches), e.g.:

{
  "tools": {
    "ssrfPolicy": {
      "allowRfc2544BenchmarkRange": true
    }
  }
}

Or extend the existing browser.ssrfPolicy to a shared/global scope.

This is a narrow, safe change:

• 198.18.0.0/15 is not used for real internal services
• In TUN environments, these IPs are ephemeral mappings to public destinations
• RFC 1918 private ranges (10.x, 172.16.x, 192.168.x) remain blocked
• Does not weaken SSRF protection for actual internal network access

Impact

This likely affects a significant number of users in regions where proxy tools with TUN mode (Clash, Surge, Shadowrocket, Quantumult X) are commonly used.

Workaround

Currently using exec + curl as a substitute for web_fetch, which works because curl's traffic goes through the TUN tunnel normally.