fix(snmp): support IPv6 in ICMP health check ping

Author: kongfei605

inputs/snmp/instances.go

@@ -377,15 +377,8 @@ func fastPingRtt(ip string, timeout int) (float64, error) {
 	rt = -1
 	p := fastping.NewPinger()
 
-	// Strip brackets from IPv6 addresses (e.g. "[::1]" -> "::1")
 	host := strings.TrimRight(strings.TrimLeft(ip, "["), "]")
-
-	network := "ip4:icmp"
-	if parsed := net.ParseIP(host); parsed != nil && parsed.To4() == nil {
-		network = "ip6:ipv6-icmp"
-	}
-
-	ra, err := net.ResolveIPAddr(network, host)
+	ra, err := net.ResolveIPAddr("ip", host)
 	if err != nil {
 		return -1, err
 	}