If you’re running Cisco devices on your network that run the IOS software, be aware of an advisory issued last week in regard to three denial of service vulnerabilities that relate to the Network Address Translation (NAT) service. Updates have been released to address all of the vulnerabilities, which affect all Cisco devices that are configured for NAT and support NAT for SIP, H.323 or H.225.0 call signaling. If NAT is not enabled on the router interface, your product is not affected, as the vulnerabilities are triggered by transit traffic that needs to be processed by the NAT feature. You can find out more details here:
http://www.cisco.com/en/US/products/products_security_advisory09186a0080b4a311.shtml