![Cisco Secure Firewall ASA Unified Communications Guide - ASA and Cisco Mobility Advantage [Cisco ASA 5500-X Series Firewalls] - Cisco Cisco Secure Firewall ASA Unified Communications Guide - ASA and Cisco Mobility Advantage [Cisco ASA 5500-X Series Firewalls] - Cisco](https://www.cisco.com/content/dam/en/us/td/i/200001-300000/270001-280000/271001-272000/271641.eps/_jcr_content/renditions/271641.jpg)
Cisco Secure Firewall ASA Unified Communications Guide - ASA and Cisco Mobility Advantage [Cisco ASA 5500-X Series Firewalls] - Cisco
![Cisco Secure Firewall ASA Unified Communications Guide - ASA and Cisco Mobility Advantage [Cisco ASA 5500-X Series Firewalls] - Cisco Cisco Secure Firewall ASA Unified Communications Guide - ASA and Cisco Mobility Advantage [Cisco ASA 5500-X Series Firewalls] - Cisco](https://www.cisco.com/content/dam/en/us/td/i/200001-300000/270001-280000/271001-272000/271642.eps/_jcr_content/renditions/271642.jpg)
Cisco Secure Firewall ASA Unified Communications Guide - ASA and Cisco Mobility Advantage [Cisco ASA 5500-X Series Firewalls] - Cisco
Why do I see the Authentication Proxy error "Allow concat is configured, but is not supported with MS-CHAPv2 authentication" while trying to authenticate to Cisco ASA?
![Authenticating Firewall Sessions (Cut-Through Proxy Feature) > Cisco ASA Authentication, Authorization, and Accounting Network Security Services | Cisco Press Authenticating Firewall Sessions (Cut-Through Proxy Feature) > Cisco ASA Authentication, Authorization, and Accounting Network Security Services | Cisco Press](https://www.ciscopress.com/content/images/chap6_9781587058196/elementLinks/ca800609.jpg)