feature preventing phantom calls (tgp500/550)

Panasonic System Networks Co., Ltd. Confidential

Feature Preventing Phantom Calls(TGP500/550)

REV 12.10

Page1

Panasonic PSNA TGP 5XX Technical Bulletin 082011-1


What are Phantom Calls?

Phantom Calls are SIP INVITES from an unexpected place with the incorrect route. INVITE is sent and not closed correctly, When TGP is answered only silence will be heard. This phenomena is known as “DoS (Denial Of Service)” or INVITE Flood.

Phantom Calls

INVITE

INVITE

Ringing

This document describes the TGP5XX functions of preventing phantom calls and how to set these functions.

Phenomena of Phantom Calls:1. Ringing, hook off and answer it but no voice, just silence.2. Sometimes anonymous caller id.3. Sometimes Request URI address is invalid.4. Sometimes Come from different SIP server.

phenomena

phenomena


The feature preventing Phantom Calls in TGP5xxTGP5xx has the following 2 features to prevent phantom calls.

1. SSAF (SIP Source Address Filter) : Block INVITE from unregistered server. If you turn on this function, TGP will not accept the call from unknown address, which are not set in the SIP servers (Register, Proxy, Presence, Outbound proxy).

Registered server address

Register : aaa.example1.netProxy : bbb.example2.netPresence : ccc.example3.netOutbound : ddd.example4.net

Calleee.unknown.net discard

From unknown server.

Call Acceptaaa.example1.net

From registered server.

2. Check username in “Request URI” in INVITE : Block INVITE with invalid username. If you turn on this function, TGP will check username of SIP URI in “Request URI” header in INVITE against registered Line ID or Phone Number. If it is not correct, TGP return 404 not found.

“404 Not found”

With wrong username

With correct username

INVITE sip:[email protected] :Registered phone number OR Line ID :12345

Incorrect

Incorrect

Correct

Correct

“100 Trying”, “180 Ringing”

INVITE sip:[email protected]

Accept

Reject


Function summaryFunction Description Parameter

NameCan set in WEB portal?

Note :

SSAF (SIP Source Address Filter)

If set to "Y", the unit receives SIP messages only from the source addresses stored in the SIP servers (registrar server, proxy server, and presence server), and not from other addresses. However, if "SIP_OUTPROXY_ADDR_[1-8]" is specified, the unit also receives SIP messages from the source address stored in the SIP outbound proxy server.

SIP_DETECT_SSAF_[1–8]

PG. 93,200

of TGP V12.10

Administrator

Guide

Yes :

Move to [VoIP ] – [Line 1] screen.

Select “Yes” at “Enable SSAF(SIP Source Address Filter)””

Some Carriers may change server source address intentionally. In such case, this function discard incoming call even it is correct one.

Check username in “Request URI” header

Specifies whether to check the username part of the SIP URI in the “Request URI" header when receiving the INVITE message with an incorrect target SIP .

-If set to "Y", the unit will return an error reply when it receives the INVITE message with an incorrect target SIP URI.-If set to "N", the unit will not check the username part of the SIP URI in the “Request URI" header.

SIP_RCV_DET_REQURI_[1–8]

PG. 200 of TGP V12.10

Administrator

Guide

No, configuration file only.

Some Carriers change user name in Request URI of INVITE request intentionally. In such case, this function discard incoming call even it is correct one.

Caution :*Some carriers may change Request URI, source address intentionally, please be careful not to reject the calls even it comes from official route/procedure.*Please back up your configuration file before updating.*Please do prior evaluation before applying these settings.


brief overview2

3

4

1. Enter the IP address into a PC's Web Browser. (refer to final page “How to access Web User Interface”)2. Login as “Administrator”.3. Move to [VoIP ] – [Line 1] screen.4. Select “Yes” at “Enable SSAF(SIP Source Address Filter)””5. Click [Save].6. Set [Line 2] – [Line 8] in a similar way.

5

How to turn on “SSAF”

Via Web user interface

Turn ON SSAF (SIP Source Address Filter)


brief overviewVia Configuration file

SIP_DETECT_SSAF_1="Y"SIP_DETECT_SSAF_2="Y"SIP_DETECT_SSAF_3="Y"SIP_DETECT_SSAF_4="Y"SIP_DETECT_SSAF_5="Y"SIP_DETECT_SSAF_6="Y"SIP_DETECT_SSAF_7="Y"SIP_DETECT_SSAF_8="Y“

1. Please back up current configuration file before updating.2. Add or change the above-mentioned setting to existing configuration file.

Note: If the same parameter is specified in a configuration file more than once, the value specified first is applied.

3. Apply Configuration file into TGP5xx

Turn ON SSAF (SIP Source Address Filter)

Caution :*Some carriers may change Request URI, source address intentionally, please be careful not to reject the calls even it comes from official route/procedure.*Please do prior evaluation before applying these settings.


Turn ON “Request URI” username checkVia Configuration file

SIP_RCV_DET_REQURI_1="Y“SIP_RCV_DET_REQURI_2="Y"SIP_RCV_DET_REQURI_3="Y"SIP_RCV_DET_REQURI_4="Y"SIP_RCV_DET_REQURI_5="Y"SIP_RCV_DET_REQURI_6="Y"SIP_RCV_DET_REQURI_7="Y"SIP_RCV_DET_REQURI_8="Y"

1. Please back up current configuration file before updating.2. Add or change the above-mentioned setting to existing configuration file.

Note: If the same parameter is specified in a configuration file more than once, the value specified first is applied.

3. Apply Configuration file into TGP5xx

Caution :*Some carriers may change Request URI, source address intentionally, In such case, this function discard incoming call even itis correct one. Please be careful not to reject the calls even it comes from official route/procedure.*Please do prior evaluation before applying these settings.

feature preventing phantom calls (tgp500/550)

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