p1.1: note IPv4-only self-IP assumption

Trace via 1.1.1.1 never learns a delegated v6 prefix.
2026-09-22 23:01:19 -07:00
parent 447842f860
commit 0598c8985b
1 changed files with 5 additions and 0 deletions
@@ -1,5 +1,10 @@
 // Package selfip discovers the host's current WAN address so the SSRF
 // guard can deny hairpin-NAT fetches of the residential IP.
+//
+// Assumption: the LAN is IPv4-only. A 1.1.1.1 trace only learns v4. If the
+// ISP ever delegates global v6, add interface-derived self prefixes
+// (net.InterfaceAddrs, deny the delegated prefix, default /56) — v6 LAN
+// hosts are then directly reachable with no hairpin NAT.
 package selfip

 import (