USG5300 L2tp can’t create the tunnel because the name of the far end tunnel configuration

Publication Date:  2012-09-13 Views:  160 Downloads:  0
Issue Description
USG5300 as LNS, PC as client, when PC dial-up, a message pop up with “link protocol stops, unable to create the L2TP”. 
Alarm Information
none
Handling Process
1 、check the configuration of equipment, no error found。
2、debug l2tp packet, as below:
USG5320 %%01L2TP/8/L2TDBG(d):  L2TP::Check SCCRQ MSG Type 1
USG5320 %%01L2TP/8/L2TDBG(d):  L2TP::Parse AVP Protocol version:  100
USG5320 %%01L2TP/8/L2TDBG(d):  L2TP::Parse AVP Framing capability : 1
USG5320 %%01L2TP/8/L2TDBG(d):  L2TP::Parse AVP Bearer capability, value: 0
USG5320 %%01L2TP/8/L2TDBG(d):  L2TP::Parse AVP Firmware revision, value: 1280
USG5320 %%01L2TP/8/L2TDBG(d):  L2TP::Parse AVP Host name, value: maple-54b168e59
USG5320 %%01L2TP/8/L2TDBG(d):  L2TP::requested host isn't in the define l2tp group , refuse the requested
USG5320 %%01L2TP/8/L2TDBG(d):  L2TP::Clear Calls On Tunnel ID=1 Reason=1
This case is cause by the different between the Tunnel name send by PC to LNS and the Tunnel name configured by LNS, And result in the enable pass the authentication.
3、 Check the PC, found the name of PC is different with the name configured in USG5300. As below:
   allow l2tp virtual-template 1 remote client1
4、 delete the  remote client1, or change the name of PC as client1, Problem solved.
Root Cause
1 configuration of LNS has problem
2 Enactment of PC has problem
This case is cause by the different between the Tunnel name send by PC to LNS and the Tunnel name configured by LNS, And result in the enable pass the authentication.
Suggestions
1、 generally, when the PC as the LAC, the name of the tunnel is the name of PC, if LNS configure the far end tunnel name , which is allow l2tp virtual-template 1 remote <tunnel name>, the name should be same with the name of PC, or don’t configure this parameter.
2 、only the group 1 of l2tp-group can don’t configure the LACname. Thus all LAC are allowed to connect in.

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