acs 4.2 :- router# test aaa group tacacs+ uid pwd .... works but not when authenticating

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Jun 17th, 2010
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I have setup ACS 4.2 and when I run


router# test aaa group tacacs+ myuser mypasswd [ legacy | new-code]



               Both options work fine



But when I try and login, over telnet, the request reaches the aaa server, but returns fail !


My commands are :-


tacacs-server host xx.xx.xx.xx single-connection port 49
tacacs-server key xxxxxxxxxxx





aaa authentication banner ^CUnauthorized access forbidden^C
aaa authentication username-prompt "Enter Username: "

aaa authentication login default group tacacs+ local

aaa authorization exec default group tacacs+ local





I dont see the banner NOR the "Enter Username:" prompt.


Also a debug aaa authentication and debug aaa subsys show that the request reaches AAA, but it simply returns fail


I had the same issue in 5.1, but that was due to the tacacs+ single-connection not being set or something similar, and the error

there was "shared secret does not match", on the AAA server logs



I am still new to 4.2, so am still trying to determine where the log files are etc, but since it works with the test command, I cant

seem to understand why it fails with telnet




Any idea why this may be happning ?


Thanks

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Jagdeep Gambhir Thu, 06/17/2010 - 07:09
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Hi,

On Layer 3 device we should have tacacs source  interface defined since there are more then one interface. To use the IP  address of a specified interface for all outgoing TACACS+  packets, use  the ip tacacs source-interface command in global configuration or server-group configuration mode.


The following  example makes TACACS+ use the IP address of subinterface  "s2" for all  outgoing TACACS+ packets:


#

ip tacacs source-interface s2

Usage Guidelines

#

Use this command to set the IP  address of a subinterface for all  outgoing TACACS+ packets. This  address is used as long as the interface  is in the up state. In this way, the TACACS+  server can use one  IP address entry associated with the network access  client instead of  maintaining a list of all IP addresses.


#

This command is especially useful  in cases where the router has many  interfaces and you want to ensure  that all TACACS+ packets from a  particular router have the same IP  address.The specified interface must have an IP address associated with  it. If  the specified subinterface does not have an IP address or is in a  down state, TACACS+ reverts to the default.  To  avoid this situation, add an IP address to the subinterface or bring  the  interface to the up state.


If there is still any issue please share the debugs.



Regards,

~JG


Do rate  helpful posts


Jatin Katyal Thu, 06/17/2010 - 07:10
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  • Cisco Employee,

Replace this command


tacacs-server host xx.xx.xx.xx single-connection port 49


with


tacacs-server host x.x.x.x


Also, let me know what error message are you getting in failed attempts? do attach the debugs.


HTH

Jk


Do rate helpful posts-



shahedvoicerite Thu, 06/17/2010 - 07:22
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I tried both the sugestion.. no luck




Below are th eoutput of debug, with some lines in BOLD to help you

find interesting lines in the log output.




Thanks





fixeddemo#sh run | inc tacacs
aaa authentication login default group tacacs+ local
aaa authorization exec default group tacacs+ local
ip tacacs source-interface FastEthernet0/1
tacacs-server host 10.1.7.15
tacacs-server key xxxxxxxxxx




fixeddemo#sh debugging
General OS:
  TACACS+ events debugging is on
  TACACS+ authentication debugging is on
  TACACS+ packets debugging is on
  AAA Authentication debugging is on
  AAA Subsystem debugs debugging is on



fixeddemo#
Jun 17 14:15:54.666: AAA/BIND(00000072): Bind i/f
Jun 17 14:15:54.666: AAA/AUTHEN/LOGIN (00000072): Pick method list 'default'
Jun 17 14:15:54.666: AAA SRV(00000072): process authen req
Jun 17 14:15:54.670: AAA SRV(00000072): Authen method=SERVER_GROUP tacacs+
Jun 17 14:15:54.670: TPLUS: Queuing AAA Authentication request 114 for processin
g
Jun 17 14:15:54.670: TPLUS: processing authentication start request id 114
Jun 17 14:15:54.670: TPLUS: Authentication start packet created for 114()
Jun 17 14:15:54.670: TPLUS: Using server 10.1.7.15
Jun 17 14:15:54.670: TPLUS(00000072)/0/NB_WAIT/45585278: Started 5 sec timeout
Jun 17 14:15:54.674: TPLUS(00000072)/0/NB_WAIT: socket event 2
Jun 17 14:15:54.674: T+: Version 192 (0xC0), type 1, seq 1, encryption 1
Jun 17 14:15:54.674: T+: session_id 3123693045 (0xBA2FC5F5), dlen 24 (0x18)
Jun 17 14:15:54.674: T+: type:AUTHEN/START, priv_lvl:1 action:LOGIN ascii
Jun 17 14:15:54.674: T+: svc:LOGIN user_len:0 port_len:6 (0x6) raddr_len:10 (0xA
) data_len:0
Jun 17 14:15:54.674: T+: user:
Jun 17 14:15:54.674: T+: port:  tty515
Jun 17 14:15:54.674: T+: rem_addr:  10.1.1.216
Jun 17 14:15:54.674: T+: data:
Jun 17 14:15:54.674: T+: End Packet
Jun 17 14:15:54.674: TPLUS(00000072)/0/NB_WAIT: wrote entire 36 bytes request
Jun 17 14:15:54.674: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:15:54.674: TPLUS(00000072)/0/READ: Would block while reading
Jun 17 14:15:54.674: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:15:54.674: TPLUS(00000072)/0/READ: read entire 12 header bytes (expect
16 bytes data)
Jun 17 14:15:54.674: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:15:54.674: TPLUS(00000072)/0/READ: read entire 28 bytes response
Jun 17 14:15:54.674: T+: Version 192 (0xC0), type 1, seq 2, encryption 1
Jun 17 14:15:54.674: T+: session_id 3123693045 (0xBA2FC5F5), dlen 16 (0x10)
Jun 17 14:15:54.674: T+: AUTHEN/REPLY status:4 flags:0x0 msg_len:10, data_len:0
fixeddemo#
Jun 17 14:15:54.674: T+: msg:  Username:
Jun 17 14:15:54.674: T+: data:
Jun 17 14:15:54.678: T+: End Packet
Jun 17 14:15:54.678: TPLUS(00000072)/0/45585278: Processing the reply packet
Jun 17 14:15:54.678: TPLUS: Received authen response status GET_USER (7)
Jun 17 14:15:54.678: AAA SRV(00000072): protocol reply GET_USER for Authenticati
on
Jun 17 14:15:54.678: AAA SRV(00000072): Return Authentication status=GET_USER
fixeddemo#
Jun 17 14:15:58.794: AAA SRV(00000072): process authen req
Jun 17 14:15:58.794: AAA SRV(00000072): Authen method=SERVER_GROUP tacacs+
Jun 17 14:15:58.794: TPLUS: Queuing AAA Authentication request 114 for processin
g
Jun 17 14:15:58.794: TPLUS: processing authentication continue request id 114
Jun 17 14:15:58.794: TPLUS: Authentication continue packet generated for 114
Jun 17 14:15:58.794: TPLUS(00000072)/0/WRITE/47194394: Started 5 sec timeout
Jun 17 14:15:58.794: T+: Version 192 (0xC0), type 1, seq 3, encryption 1
Jun 17 14:15:58.794: T+: session_id 3123693045 (0xBA2FC5F5), dlen 10 (0xA)
Jun 17 14:15:58.794: T+: AUTHEN/CONT msg_len:5 (0x5), data_len:0 (0x0) flags:0x0
Jun 17 14:15:58.794: T+: User msg:
Jun 17 14:15:58.794: T+: User data:
Jun 17 14:15:58.794: T+: End Packet
Jun 17 14:15:58.794: TPLUS(00000072)/0/WRITE: wrote entire 22 bytes request
Jun 17 14:15:58.798: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:15:58.798: TPLUS(00000072)/0/READ: read entire 12 header bytes (expect
16 bytes data)
Jun 17 14:15:58.798: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:15:58.798: TPLUS(00000072)/0/READ: read entire 28 bytes response
Jun 17 14:15:58.798: T+: Version 192 (0xC0), type 1, seq 4, encryption 1
Jun 17 14:15:58.798: T+: session_id 3123693045 (0xBA2FC5F5), dlen 16 (0x10)
fixeddemo#
Jun 17 14:15:58.798: T+: AUTHEN/REPLY status:5 flags:0x1 msg_len:10, data_len:0
Jun 17 14:15:58.798: T+: msg:  Password:
Jun 17 14:15:58.798: T+: data:
Jun 17 14:15:58.798: T+: End Packet
Jun 17 14:15:58.798: TPLUS(00000072)/0/47194394: Processing the reply packet
Jun 17 14:15:58.798: TPLUS: Received authen response status GET_PASSWORD (8)
Jun 17 14:15:58.798: AAA SRV(00000072): protocol reply GET_PASSWORD for Authenti
cation
Jun 17 14:15:58.798: AAA SRV(00000072): Return Authentication status=GET_PASSWOR
D
fixeddemo#
Jun 17 14:16:02.502: AAA SRV(00000072): process authen req
Jun 17 14:16:02.502: AAA SRV(00000072): Authen method=SERVER_GROUP tacacs+
Jun 17 14:16:02.502: TPLUS: Queuing AAA Authentication request 114 for processin
g
Jun 17 14:16:02.502: TPLUS: processing authentication continue request id 114
Jun 17 14:16:02.502: TPLUS: Authentication continue packet generated for 114
Jun 17 14:16:02.502: TPLUS(00000072)/0/WRITE/47194394: Started 5 sec timeout
Jun 17 14:16:02.502: T+: Version 192 (0xC0), type 1, seq 5, encryption 1
Jun 17 14:16:02.502: T+: session_id 3123693045 (0xBA2FC5F5), dlen 14 (0xE)
Jun 17 14:16:02.502: T+: AUTHEN/CONT msg_len:9 (0x9), data_len:0 (0x0) flags:0x0
Jun 17 14:16:02.502: T+: User msg:
Jun 17 14:16:02.502: T+: User data:
Jun 17 14:16:02.502: T+: End Packet
Jun 17 14:16:02.506: TPLUS(00000072)/0/WRITE: wrote entire 26 bytes request
Jun 17 14:16:02.550: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:16:02.550: TPLUS(00000072)/0/READ: read entire 12 header bytes (expect
6 bytes data)
Jun 17 14:16:02.550: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:16:02.550: TPLUS(00000072)/0/READ: read entire 18 bytes response
Jun 17 14:16:02.550: T+: Version 192 (0xC0), type 1, seq 6, encryption 1
Jun 17 14:16:02.554: T+: session_id 3123693045 (0xBA2FC5F5), dlen 6 (0x6)
fixeddemo#
Jun 17 14:16:02.554: T+: AUTHEN/REPLY status:2 flags:0x0 msg_len:0, data_len:0
Jun 17 14:16:02.554: T+: msg:
Jun 17 14:16:02.554: T+: data:
Jun 17 14:16:02.554: T+: End Packet
Jun 17 14:16:02.554: TPLUS(00000072)/0/47194394: Processing the reply packet
Jun 17 14:16:02.554: TPLUS: Received authen response status FAIL (3)
Jun 17 14:16:02.554: AAA SRV(00000072): protocol reply FAIL for Authentication
Jun 17 14:16:02.554: AAA SRV(00000072): Return Authentication status=FAIL
fixeddemo#



[ The output below is for the next Username: prompt I believe]Jun 17 14:16:04.554: AAA/AUTHEN/LOGIN (00000072): Pick method list 'default'
Jun 17 14:16:04.554: AAA SRV(00000072): process authen req
Jun 17 14:16:04.554: AAA SRV(00000072): Authen method=SERVER_GROUP tacacs+
Jun 17 14:16:04.554: TPLUS: Queuing AAA Authentication request 114 for processin
g
Jun 17 14:16:04.554: TPLUS: processing authentication start request id 114
Jun 17 14:16:04.554: TPLUS: Authentication start packet created for 114()
Jun 17 14:16:04.554: TPLUS: Using server 10.1.7.15
Jun 17 14:16:04.554: TPLUS(00000072)/0/NB_WAIT/47194394: Started 5 sec timeout
Jun 17 14:16:04.558: TPLUS(00000072)/0/NB_WAIT: socket event 2
Jun 17 14:16:04.558: T+: Version 192 (0xC0), type 1, seq 1, encryption 1
Jun 17 14:16:04.558: T+: session_id 2365877689 (0x8D046DB9), dlen 24 (0x18)
Jun 17 14:16:04.558: T+: type:AUTHEN/START, priv_lvl:1 action:LOGIN ascii
Jun 17 14:16:04.558: T+: svc:LOGIN user_len:0 port_len:6 (0x6) raddr_len:10 (0xA
) data_len:0
Jun 17 14:16:04.558: T+: user:
Jun 17 14:16:04.558: T+: port:  tty515
Jun 17 14:16:04.558: T+: rem_addr:  10.1.1.216
Jun 17 14:16:04.558: T+: data:
Jun 17 14:16:04.558: T+: End Packet
Jun 17 14:16:04.558: TPLUS(00000072)/0/NB_WAIT: wrote entire 36 bytes request
Jun 17 14:16:04.558: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:16:04.558: TPLUS(00000072)/0/READ: Would block while reading
Jun 17 14:16:04.562: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:16:04.562: TPLUS(00000072)/0/READ: read entire 12 header bytes (expect
43 bytes data)
Jun 17 14:16:04.562: TPLUS(00000072)/0/READ: socket event 1
Jun 17 14:16:04.562: TPLUS(00000072)/0/READ: read entire 55 bytes response
Jun 17 14:16:04.562: T+: Version 192 (0xC0), type 1, seq 2, encryption 1
Jun 17 14:16:04.562: T+: session_id 2365877689 (0x8D046DB9), dlen 43 (0x2B)
Jun 17 14:16:04.562: T+: AUTHEN/REPLY status:4 flags:0x0 msg_len:37, data_len:0
Jun 17 14:16:04.562: T+: msg:   0x0A User Access Verification 0x0A  0x0A Usernam
e:
fixeddemo#
Jun 17 14:16:04.562: T+: data:
Jun 17 14:16:04.562: T+: End Packet
Jun 17 14:16:04.562: TPLUS(00000072)/0/47194394: Processing the reply packet
Jun 17 14:16:04.562: TPLUS: Received authen response status GET_USER (7)
Jun 17 14:16:04.562: AAA SRV(00000072): protocol reply GET_USER for Authenticati
on
Jun 17 14:16:04.562: AAA SRV(00000072): Return Authentication status=GET_USER
fixeddemo#

shahedvoicerite Thu, 06/17/2010 - 07:27
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I had a setting in the ACS Group for the user


The setting was


Per Group Defined Network Access Restrictions
with a checkbox for define ip based access restrictions.



Nothing else was set... no aaa clients were selected.



I dont know what this does, or why I had set it up... Removing it solved my issue.




THANKS

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