fix: skip TTL update for OPT records

wwqgtxx · wwqgtxx · commit cc376acc5b5d · 2026-05-09T22:14:25.000+08:00
diff --git a/dns/util.go b/dns/util.go
@@ -96,6 +96,9 @@ func setMsgTTL(msg *D.Msg, ttl uint32) {
 	}
 
 	for _, extra := range msg.Extra {
+		if extra.Header().Rrtype == D.TypeOPT { // TTL section in OPT is the extended RCODE and flags (RFC 6891), not real TTL value
+			continue
+		}
 		extra.Header().Ttl = ttl
 	}
 }

Original file line number	Diff line number	Diff line change
`@@ -96,6 +96,9 @@ func setMsgTTL(msg *D.Msg, ttl uint32) {`
`96`	`96`	`}`
`97`	`97`
`98`	`98`	`for _, extra := range msg.Extra {`
	`99`	`+ if extra.Header().Rrtype == D.TypeOPT { // TTL section in OPT is the extended RCODE and flags (RFC 6891), not real TTL value`
	`100`	`+ continue`
	`101`	`+ }`
`99`	`102`	`extra.Header().Ttl = ttl`
`100`	`103`	`}`
`101`	`104`	`}`