tacacs+ and Cisco 2950 configuration

Unanswered Question
Mar 6th, 2008
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Hi everyone!

I want to authenticate to my Switch via Tacacs+. It runs fine as long as I define Users and passwords in the /etc/tac-plus/tacacs.conf. But when I try to authenticate against a MySQL DB or the /etc/passwd file, authentication fails.

With the config below, I'm able to login with username fred. In MySQL DB a user 'test' with password ENCRYPT('test') is correctly set up. I use the DB skel which comes with tacacs+ (in Debian it's in /usr/share/docs/tac-plus, manual from http://www.gazi.edu.tr/tacacs/docs/tacacs_db.txt)


My tacacs+ config:

# /etc/tac-plus/tacacs.conf

### TACACS+ Config

# Auth-Key

key = some_key

#default authentication = file /etc/passwd

default authentication = db mysql://user:[email protected]/tacacs/auth?usern&passwd

accounting file = /var/log/tac-plus/account.log

###### USER ######

user = DEFAULT {

default service = permit


#user = DEFAULT {

# service = ppp

# protocol = ip {

# }


# Enable-User

#user = $enable$ {

# login = cleartext test


user = fred {

default service = permit

login = cleartext fred_pw




My Cisco config:

switch#sh ru

Building configuration...

[some info]

version 12.1

no service pad

service timestamps debug uptime

service timestamps log uptime

service password-encryption


hostname MySwitch


aaa new-model

aaa group server tacacs+ TACSERV



aaa authentication login default group TACSERV local line

enable secret secret_enable_pw


username rescue secret secret_rescue_pw

ip subnet-zero


spanning-tree extend system-id



interface FastEthernet0/1

switchport access vlan 180

switchport mode trunk

switchport nonegotiate

no ip address


[some FastEthernet and GigabitEthernet Configuration]

ip default-gateway

ip http server


tacacs-server host key some_key


line con 0

exec-timeout 0 0

line vty 5 15


ntp server



It would be great if someone could help.



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fredfisch Thu, 03/06/2008 - 23:00
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I realized that Debian only stores usernames in /etc/passwd - the user's password is stored in /etc/shadow.

I manually edited the passwd file to get the password in. Result: authentication works with /etc/passwd. But when I point to /etc/shadow in the configuration file, authentication doesn't work.

Is there a way to get tacacs+ to use the /etc/shadow properly or to configure Debian not to use /etc/shadow?

The other big problem - authentication against MySQL - doesn't work, yet.

Any Hints?




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