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Cisco Bug: CSCvt75633 - It takes long until FlexVPN IKEv2 tunnel re-establishes when tunnel flaps

Last Modified

Sep 10, 2020

Products (14)

  • Cisco IOS
  • Cisco 4221 Integrated Services Router
  • Cisco ASR 1000 Series IOS XE SD-WAN
  • Cisco 4321 Integrated Services Router
  • Cisco ASR 1002-X Router
  • Cisco 4331 Integrated Services Router
  • Cisco ASR 1001-X Router
  • Cisco 4351 Integrated Services Router
  • Cisco ISR 4000 Series IOS XE SD-WAN
  • Cisco ASR 1002-HX Router
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Known Affected Releases

16.3.7 16.9.4 17.3.1

Description (partial)

FlexVPN client is starting negotiation before the Tunnel interface comes up. As a result (in case of tunnel flaps) it takes almost 4 minutes until tunnel re-establishes. 

Until the tunnel interface goes up, the negotiation failed with Auth exchange failed.

*Apr  9 08:35:01.762: %FLEXVPN-6-FLEXVPN_CONNECTION_DOWN: FlexVPN(flex) Client_public_addr = Server_public_addr =
*Apr  9 08:35:01.949: IKEv2:(SESSION ID = 1,SA ID = 2):Error in settig received config mode data
*Apr  9 08:35:01.949: IKEv2:(SESSION ID = 1,SA ID = 2):Auth exchange failed
*Apr  9 08:35:01.950: IKEv2-ERROR:(SESSION ID = 1,SA ID = 2):: Auth exchange failed
*Apr  9 08:35:01.950: IKEv2:(SESSION ID = 1,SA ID = 2):Abort exchange

*Apr  9 08:35:03.744: %LINK-3-UPDOWN: Interface Tunnel2, changed state to up

*Apr  9 08:38:21.769: %FLEXVPN-6-FLEXVPN_CONNECTION_DOWN: FlexVPN(flex) Client_public_addr = Server_public_addr =

It takes 3 minutes and 18 seconds until %FLEXVPN-6-FLEXVPN_CONNECTION_DOWN process starts the next try to re-establish the tunnel.

FlexVPN IKEv2 with Radius Authentication.
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