Cisco SSL VPN + AD RADIUS authentication


currently we are using MS RRAS VPN but we are going replace it to Cisco ASA 5510-X with Cisco AnyConnect. I would like to know whether I have right understood the authentication process. I have the following schema:

  1. VPN client connects to Cisco VPN
  2. Cisco VPN asks DUO Proxy for the authentication
  3. Duo Proxy asks MS RADIUS for the authentication
  4. RADIUS says to Dup Proxy “OK”
  5. DUO Proxy asks DUO server for the authentication and User approves it by DUO Mobile
  6. DOU Proxy answers Cisco VPN “OK” and Cisco VPN establishes VPN connection.

Is everything right?


Take a look at the networking diagram and accompanying description at the bottom of this page:

Your upstream RADIUS server (NPS or whatever) would be #3. Alternatively, you could point the Duo proxy straight at AD, so your domain controller would be #3.


Hello Kristina,
this is my configuration file of DUO Proxy:


then I try to check VPN in Cisco, I get an error:
test aaa-server authentication Duo host username vpn_asa password 1q2wazsxDCFV

2018-01-02T11:31:29+0100 [-] Duo Security Authentication Proxy 2.7.0 - Init Complete
2018-01-02T11:31:29+0100 [-] RadiusClient starting on 56935
2018-01-02T11:31:29+0100 [-] Starting protocol <duoauthproxy.lib.radius.client.RadiusClient instance at 0x02A5CC88>
2018-01-02T11:31:40+0100 [DuoForwardServer (UDP)] Packet dump - received from
2018-01-02T11:31:40+0100 [DuoForwardServer (UDP)] '\x014\x00A\xff-\xa8\xbc\x95N\x85Q\xb5\xb2A\xe0\x81\x97i[\x01\tvpn_asa\x02\x12\xa77e\xfe\xf9\x113 \xdde\xf71tt\xcc\xde\x04\x06\n\xfe\x01\xc8\x
2018-01-02T11:31:40+0100 [DuoForwardServer (UDP)] Sending request from to radius_server_auto
2018-01-02T11:31:40+0100 [DuoForwardServer (UDP)] Received new request id 52 from ('', 20747)
2018-01-02T11:31:40+0100 [DuoForwardServer (UDP)] (('', 20747), 52): login attempt for username u'vpn_asa'
2018-01-02T11:31:40+0100 [DuoForwardServer (UDP)] Sending request for user u'vpn_asa' to ('', 1812) with id 212
2018-01-02T11:31:40+0100 [DuoForwardServer (UDP)] Packet dump - sent to
2018-01-02T11:31:40+0100 [DuoForwardServer (UDP)] '\x01\xd4\x00A\xa0;|\xd5\x83\x0fP\x8a-Y\xd7,\x0f$\xa5\x98\x01\tvpn_asa\x02\x12\xc3\xf4\xefM\x83\xc2OwT\xfbe\x8c\xfc\xb7\xad\x12\x04\x06\n\xfe\
2018-01-02T11:31:40+0100 [RadiusClient (UDP)] Packet dump - received from
2018-01-02T11:31:40+0100 [RadiusClient (UDP)] '\x02\xd4\x00fi\x9f\x1c3\xb3xI\xaa\xc6Z\x18O\xaf\xd7\xa2\xbf\x07\x06\x00\x00\x00\x01\x06\x06\x00\x00\x00\x02\x19.\x9e"\t\xc1\x00\x00\x017\x00\x01\
2018-01-02T11:31:40+0100 [RadiusClient (UDP)] Got response for id 212 from ('', 1812); code 2
2018-01-02T11:31:40+0100 [RadiusClient (UDP)] http POST to user=vpn_asa
2018-01-02T11:31:40+0100 [duoauthproxy.lib.http._DuoHTTPClientFactory#info] Starting factory <_DuoHTTPClientFactory:>
2018-01-02T11:31:41+0100 [HTTPPageGetter (TLSMemoryBIOProtocol),client] Duo preauth call failed
        Traceback (most recent call last):
          File "twisted\internet\defer.pyc", line 588, in _runCallbacks

          File "twisted\internet\defer.pyc", line 1184, in gotResult

          File "twisted\internet\defer.pyc", line 1126, in _inlineCallbacks

          File "twisted\python\failure.pyc", line 389, in throwExceptionIntoGenerator

        --- <exception caught here> ---
          File "duoauthproxy\lib\radius\duo_server.pyc", line 141, in preauth

          File "twisted\internet\defer.pyc", line 1126, in _inlineCallbacks

          File "twisted\python\failure.pyc", line 389, in throwExceptionIntoGenerator

          File "duoauthproxy\lib\duo_async.pyc", line 182, in preauth

          File "twisted\internet\defer.pyc", line 1128, in _inlineCallbacks

          File "duoauthproxy\lib\duo_async.pyc", line 145, in call

          File "duoauthproxy\lib\duo_async.pyc", line 159, in _parse_response

        duoauthproxy.lib.duo_async.DuoAPIFailClosedError: 40102: Invalid integration key in request credentials

2018-01-02T11:31:41+0100 [HTTPPageGetter (TLSMemoryBIOProtocol),client] (('', 20747), 52): Denied Duo login on unexpected failure
2018-01-02T11:31:41+0100 [HTTPPageGetter (TLSMemoryBIOProtocol),client] (('', 20747), 52): Returning response code 3: AccessReject
2018-01-02T11:31:41+0100 [HTTPPageGetter (TLSMemoryBIOProtocol),client] (('', 20747), 52): Sending response
2018-01-02T11:31:41+0100 [HTTPPageGetter (TLSMemoryBIOProtocol),client] Packet dump - sent to
2018-01-02T11:31:41+0100 [HTTPPageGetter (TLSMemoryBIOProtocol),client] '\x034\x00<:s\x97\xb9\xdd3\x1b\xe7C\x83\xfbkR\xef\x8c\xdd\x12(Denied Duo login on unexpected failure'
2018-01-02T11:31:41+0100 [duoauthproxy.lib.http._DuoHTTPClientFactory#info] Stopping factory <_DuoHTTPClientFactory:>

How can i fix it?


it is very strange. We have also DUO proxy for RRAS.
I have taken ikey and skey from this App - it works!
But why the ikey and skey for Cisco don’t work?
Acount ID: 0199-1825-13


Did you create the right kind of Cisco application (you want “Cisco RADIUS VPN” instead of “Cisco SSL VPN”)? Perhaps the Cisco application information was copied/pasted incorrectly?

I suggest you contact Duo support about this issue - it’s pretty much impossible to troubleshoot this error without your actual integration information (ikey and host) but we don’t want you sharing that info to the whole community.