ISDN GW Hacks issue (How to Block at VCS-E)

[f-foster]

I have been having a rash of external calls that are attempting a SIP connection to  my VCS-E then dialing up over our ISDN Tandberg GW.  We have had our phone lines blocked several times now because these calls go to Middle Eastern countries sometimes that are on watch lists.  I have been blocking them under Registrations one at a time but just wondering if there is some way of locking things down much further to not allow this type of hack to occur.

Call summary

You are here: Status Calls Calls Call summary

Call Information
State	Connection Failed
Start time	2012-01-30 13:26:09
End time	2012-01-30 13:26:09
Duration	0 seconds
Tag	e10a5c10-4b6f-11e1-8a80-0010f31ada6c

Bandwidth
Requested	0 kbps
Allocated	0 kbps

Incoming call setup parameters
Source alias 1	sip:unknown@194.73.113.96 (Url)
Target alias 1	sip:000000442032987272@38.98.229.169 (Url)
Protocol	SIP
Address	194.73.113.96:5060
Transport	UDP
Reason	Unsupported URI Scheme
Cause	416

Outgoing call setup parameters
Source alias 1	unknown@194.73.113.96 (Url)
Target alias 1	sip:000000442032987272@38.98.229.169 (Url)
Protocol	SIP
Address	38.98.229.170:39031
Transport	TLS

[davidhouska]

Hi,

Check this document:

Cisco TelePresence Video Communication Server Basic Configuration (Control with Expressway)

http://www.cisco.com/en/US/docs/telepresence/infrastructure/vcs/config_guide/Cisco_VCS_Basic_Configuration_Cisco_VCS_Control_with_Cisco_VCS_Expressway_Deployment_Guide_X7-1.pdf

Chapter: Optional configuration steps/Step 16: Restrict access to ISDN gateways

Regards,

David

[Julio Cascante]

Hello,

What IOS ver is your GW running.

On newer versions there a command called Ip address trusted authenticate under voice service voip which is going to allow calls coming from devices that have a trusted IP address.

Try upgrading your IOS to the newest version.