diff --git a/build_static.sh b/build_static.sh
index 8f24c24..7e8220a 100644
--- a/build_static.sh
+++ b/build_static.sh
@@ -1,5 +1,8 @@
 #!/bin/sh
 
+# Thanks for the idea to use musl!
+# https://www.moiji-mobile.com/2017/10/15/static-binaries-for-go-with-docker/
+
 set -ex
 
 apk update
diff --git a/config/config.go b/config/config.go
index 4eff8f3..6db0869 100644
--- a/config/config.go
+++ b/config/config.go
@@ -21,6 +21,7 @@ type InterfacesConfig struct {
 	Type         string `config:"type"`
 	ReadFile     string `config:"read_file"`
 	WriteFile    string `config:"write_file"`
+	PortRange    string `config:"port_range"`
 	Snaplen      int    `config:"snaplen"`
 	BufferSizeMb int    `config:"buffer_size_mb"`
 	ReadSpeed    bool   `config:"top_speed"`
diff --git a/example/rtp_rtcp_sip.pcap b/example/rtp_rtcp_sip.pcap
new file mode 100644
index 0000000..59dd1a2
Binary files /dev/null and b/example/rtp_rtcp_sip.pcap differ
diff --git a/main.go b/main.go
index e64f3bb..0d7585b 100644
--- a/main.go
+++ b/main.go
@@ -25,12 +25,13 @@ func parseFlags() {
 	var keepLogFiles int
 
 	flag.StringVar(&ifaceConfig.Device, "i", "", "Listen on interface")
-	flag.StringVar(&ifaceConfig.Type, "t", "pcap", "Capture types are [af_packet, pcap, file]")
-	flag.StringVar(&ifaceConfig.ReadFile, "rf", "", "Read packets from file. Please use -t file")
-	flag.StringVar(&ifaceConfig.WriteFile, "wf", "", "Write packets to file")
-	flag.IntVar(&ifaceConfig.Loop, "lp", 1, "Loop count over ReadFile")
-	flag.BoolVar(&ifaceConfig.ReadSpeed, "rs", false, "Maximum read speed. Doesn't use packet timestamps")
-	flag.IntVar(&ifaceConfig.Snaplen, "s", 32768, "Snap length")
+	flag.StringVar(&ifaceConfig.Type, "t", "pcap", "Capture types are [pcap, af_packet]")
+	flag.StringVar(&ifaceConfig.ReadFile, "rf", "", "Read packets from pcap file")
+	flag.StringVar(&ifaceConfig.WriteFile, "wf", "", "Write packets to pcap file")
+	flag.IntVar(&ifaceConfig.Loop, "lp", 1, "Loop count over ReadFile. Use 0 to loop forever")
+	flag.BoolVar(&ifaceConfig.ReadSpeed, "rs", false, "Maximum pcap read speed. Doesn't use packet timestamps")
+	flag.IntVar(&ifaceConfig.Snaplen, "s", 32768, "Snaplength")
+	flag.StringVar(&ifaceConfig.PortRange, "pr", "5060-5090", "Portrange to capture SIP")
 	flag.IntVar(&ifaceConfig.BufferSizeMb, "b", 64, "Interface buffersize (MB)")
 	flag.IntVar(&keepLogFiles, "kl", 4, "Rotate the number of log files")
 	flag.StringVar(&logging.Level, "l", "info", "Log level [debug, info, warning, error]")
@@ -38,10 +39,10 @@ func parseFlags() {
 	flag.StringVar(&fileRotator.Path, "p", "./", "Log filepath")
 	flag.StringVar(&fileRotator.Name, "n", "heplify.log", "Log filename")
 	flag.Uint64Var(&rotateEveryKB, "r", 16384, "Log filesize (KB)")
-	flag.StringVar(&config.Cfg.Mode, "m", "SIP", "Capture modes [DNS, LOG, SIP, RTCP, TLS]")
+	flag.StringVar(&config.Cfg.Mode, "m", "SIP", "Capture modes [DNS, LOG, SIP, SIPRTCP, TLS]")
 	flag.BoolVar(&config.Cfg.Dedup, "dd", true, "Deduplicate packets")
-	flag.StringVar(&config.Cfg.Filter, "fi", "", "Filter out interesting packets like SIP INVITES, Handshakes ...")
-	flag.StringVar(&config.Cfg.Discard, "di", "", "Discard uninteresting packets like SIP OPTIONS, HTTP Requests ...")
+	flag.StringVar(&config.Cfg.Filter, "fi", "", "Filter interesting packets")
+	flag.StringVar(&config.Cfg.Discard, "di", "", "Discard uninteresting packets")
 	flag.StringVar(&config.Cfg.HepServer, "hs", "127.0.0.1:9060", "HEP Server address")
 	flag.Parse()
 
diff --git a/protos/rtcp.go b/protos/rtcp.go
index 38880c4..30cdf28 100644
--- a/protos/rtcp.go
+++ b/protos/rtcp.go
@@ -183,7 +183,7 @@ func ParseRTCP(data []byte) ([]byte, error) {
 	offset := 0
 
 	for dataLen > 0 {
-		if dataLen%4 != 0 || dataLen < 4 {
+		if dataLen < 4 || dataLen > 576 {
 			return nil, fmt.Errorf("Fishy RTCP packet=%v length=%d", data, dataLen)
 		}
 
diff --git a/sniffer/sniffer.go b/sniffer/sniffer.go
index 781d88e..501d064 100644
--- a/sniffer/sniffer.go
+++ b/sniffer/sniffer.go
@@ -95,11 +95,11 @@ func (sniffer *SnifferSetup) setFromConfig(cfg *config.InterfacesConfig) error {
 
 	switch sniffer.mode {
 	case "SIP":
-		sniffer.filter = "(greater 256 and portrange 5060-5090 or ip[6:2] & 0x1fff != 0) or (vlan and (greater 256 and portrange 5060-5090 or ip[6:2] & 0x1fff != 0))"
+		sniffer.filter = "(greater 256 and portrange " + sniffer.config.PortRange + " or ip[6:2] & 0x1fff != 0) or (vlan and (greater 256 and portrange " + sniffer.config.PortRange + " or ip[6:2] & 0x1fff != 0))"
 	case "RTCP":
 		sniffer.filter = "(ip and ip[6] & 0x2 = 0 and ip[6:2] & 0x1fff = 0 and udp and udp[8] & 0xc0 = 0x80 and udp[9] >= 0xc8 && udp[9] <= 0xcc)"
 	case "SIPRTCP":
-		sniffer.filter = "(greater 256 and portrange 5060-5090 or ip[6:2] & 0x1fff != 0) or (ip and ip[6] & 0x2 = 0 and ip[6:2] & 0x1fff = 0 and udp and udp[8] & 0xc0 = 0x80 and udp[9] >= 0xc8 && udp[9] <= 0xcc)"
+		sniffer.filter = "(greater 256 and portrange " + sniffer.config.PortRange + " or ip[6:2] & 0x1fff != 0) or (ip and ip[6] & 0x2 = 0 and ip[6:2] & 0x1fff = 0 and udp and udp[8] & 0xc0 = 0x80 and udp[9] >= 0xc8 && udp[9] <= 0xcc)"
 	case "LOG":
 		sniffer.filter = "greater 128 and port 514"
 	case "DNS":
@@ -108,7 +108,7 @@ func (sniffer *SnifferSetup) setFromConfig(cfg *config.InterfacesConfig) error {
 		sniffer.filter = "tcp and port 443 and tcp[(((tcp[12:1] & 0xf0) >> 2)):1] = 0x16 and ((tcp[(((tcp[12:1] & 0xf0) >> 2)+5):1] = 0x01) or (tcp[(((tcp[12:1] & 0xf0) >> 2)+5):1] = 0x02))"
 	default:
 		sniffer.mode = "SIP"
-		sniffer.filter = "(greater 256 and portrange 5060-5090 or ip[6:2] & 0x1fff != 0) or (vlan and (greater 256 and portrange 5060-5090 or ip[6:2] & 0x1fff != 0))"
+		sniffer.filter = "(greater 256 and portrange " + sniffer.config.PortRange + " or ip[6:2] & 0x1fff != 0) or (vlan and (greater 256 and portrange " + sniffer.config.PortRange + " or ip[6:2] & 0x1fff != 0))"
 	}
 
 	logp.Info("Sniffer type: [%s] device: [%s] mode: [%s]", sniffer.config.Type, sniffer.config.Device, sniffer.mode)
@@ -167,13 +167,17 @@ func (sniffer *SnifferSetup) Init(testMode bool, mode string, factory WorkerFact
 	sniffer.mode = mode
 
 	if interfaces.Device == "" && interfaces.ReadFile == "" {
-		fmt.Printf("\nPlease use one of the following devices:\n\n")
+		fmt.Printf("Please use one of the following devices:\n\n")
 		_, err := ListDeviceNames(false, false)
 		if err != nil {
 			return fmt.Errorf("getting devices list: %v", err)
 		}
 		fmt.Println("")
 		os.Exit(1)
+	} else if interfaces.Device == "any" && interfaces.Type == "pcap" {
+		fmt.Println("Interface 'any' and capture type 'pcap' will break VLAN capture!")
+		fmt.Println("To listen on interface 'any' please use 'af_packet' capture type!")
+		os.Exit(1)
 	}
 
 	if !testMode {