[30655] in Kerberos

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Re: Problem with kerberos telnet option

daemon@ATHENA.MIT.EDU (Richard E. Silverman)
Wed Jan 28 15:07:28 2009

From: "Richard E. Silverman" <res@qoxp.net>
Date: Wed, 28 Jan 2009 13:53:06 -0500
Message-ID: <m2bptri7ot.fsf@darwin.oankali.net>
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To: kerberos@mit.edu
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Errors-To: kerberos-bounces@mit.edu

> 
> I am trying to setup a test kdc server and workstation.
> After I did the setup I can login as user5 using the kerberos
> password. But there still seems to be a problem.
> 
> When I telnet from station5 (kerberos server) to station6
> (workstation) I get the following error [krb5-telnet is on]
> -------------------------------
> Waiting for encryption to be negotiated...
> 
> Negotiation of authentication, which is required for encryption,
> has failed.  Good-bye.
> ---------------------------------------

Try setting client-side debug authentication debugging to see what's going on:

sys1:~% telnet
telnet> set authd
auth debugging enabled
telnet> open -a seraph.lionaka.net
Trying ...
Connected to seraph.lionaka.net
Escape character is '^]'.
>>>TELNET: I support auth type 2 6
>>>TELNET: I support auth type 2 2
>>>TELNET: I support auth type 2 0
>>>TELNET: auth_send got: 02 06 02 02 02 00
>>>TELNET: He supports 2
>>>TELNET: He supports 2
>>>TELNET: Trying 2 2
>>>IS:0: [0] (485) 6e 82 01 e1 30 82 01 dd a0 03 02 01 05 a1 03 02
telnet: Sent Kerberos V5 credentials to server
>>>TELNET: Using type 2
[ Kerberos V5 accepts you as ``res@LIONAKA.NET'' ]
Last login: Tue Jan 27 21:57:55
seraph:~% 


> When I login to either station5 or station6 using the user5 kerberos
> password (login or ssh), everything seems to be working. But when I go
> from ssh from station6 to station5 it request another login.  I
> thought kerberos would only require me to login to station6 and then I
> could ssh directly to station5 without re-entering the password.
> 
> Following are my krb5kdc.log messages as mapped by step.
> Following this are my /etc/krb5.conf, /var/kerberos/krb5kdc/kdc.conf
> files and my results from getprincs.
> 
> What I am trying to determine is what are these log messages telling
> me and do they give an indication of what maybe or is my problem.
> 
> ####### telnet from station5 to station6
> ####### telnet -Fxl user5 station6.example.com
> 
> Jan 19 22:01:51 station5 krb5kdc[1876](info): TGS_REQ (1 etypes {1})
> 192.168.1.5: ISSUE: authtime 1232423977, etypes {rep=16 tkt=16 ses=1},
> user5@STATION5.EXAMPLE.COM for host/
> station6.example.com@STATION5.EXAMPLE.COM
> Jan 19 22:01:51 station5 krb5kdc[1876](info): TGS_REQ (1 etypes {1})
> 192.168.1.5: ISSUE: authtime 1232423977, etypes {rep=16 tkt=16 ses=1},
> user5@STATION5.EXAMPLE.COM for host/
> station6.example.com@STATION5.EXAMPLE.COM
> Jan 19 22:01:51 station5 krb5kdc[1876](info): TGS_REQ (1 etypes {1})
> 192.168.1.5: ISSUE: authtime 1232423977, etypes {rep=16 tkt=16 ses=1},
> user5@STATION5.EXAMPLE.COM for krbtgt/
> STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM
> Jan 19 22:01:51 station5 krb5kdc[1876](info): TGS_REQ (1 etypes {1})
> 192.168.1.5: ISSUE: authtime 1232423977, etypes {rep=16 tkt=16 ses=1},
> user5@STATION5.EXAMPLE.COM for krbtgt/
> STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM
> 
> 
> 
> 
> ###### Following is the messages in krb5kdc.log after ssh login
> ###### from a computer outside realm to
> ###### user5@station6.example.com
> 
> Jan 19 21:56:22 station5 krb5kdc[1876](info): AS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: NEEDED_PREAUTH: user5@STATION5.EXAMPLE.COM
> for krbtgt/STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM, Additional pre-
> authentication required
> Jan 19 21:56:22 station5 krb5kdc[1876](info): AS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: NEEDED_PREAUTH: user5@STATION5.EXAMPLE.COM
> for krbtgt/STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM, Additional pre-
> authentication required
> Jan 19 21:56:22 station5 krb5kdc[1876](info): AS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: ISSUE: authtime 1232423782, etypes {rep=16
> tkt=16 ses=16}, user5@STATION5.EXAMPLE.COM for krbtgt/
> STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM
> Jan 19 21:56:22 station5 krb5kdc[1876](info): AS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: ISSUE: authtime 1232423782, etypes {rep=16
> tkt=16 ses=16}, user5@STATION5.EXAMPLE.COM for krbtgt/
> STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM
> Jan 19 21:56:22 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: ISSUE: authtime 1232423782, etypes {rep=16
> tkt=16 ses=16}, user5@STATION5.EXAMPLE.COM for host/
> station6.example.com@STATION5.EXAMPLE.COM
> Jan 19 21:56:22 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: ISSUE: authtime 1232423782, etypes {rep=16
> tkt=16 ses=16}, user5@STATION5.EXAMPLE.COM for host/
> station6.example.com@STATION5.EXAMPLE.COM
> 
> 
> ##### this is after starting the ssh login from station6 to station5
> ##### ssh station5.example.com -l user5
> ##### password has not been entered
> 
> Jan 19 21:59:05 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: UNKNOWN_SERVER: authtime 1232423782,
> user5@STATION5.EXAMPLE.COM for host/station5@STATION5.EXAMPLE.COM,
> Server not found in Kerberos database
> Jan 19 21:59:05 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: UNKNOWN_SERVER: authtime 1232423782,
> user5@STATION5.EXAMPLE.COM for host/station5@STATION5.EXAMPLE.COM,
> Server not found in Kerberos database
> Jan 19 21:59:05 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: UNKNOWN_SERVER: authtime 1232423782,
> user5@STATION5.EXAMPLE.COM for host/station5@STATION5.EXAMPLE.COM,
> Server not found in Kerberos database
> Jan 19 21:59:05 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: UNKNOWN_SERVER: authtime 1232423782,
> user5@STATION5.EXAMPLE.COM for host/station5@STATION5.EXAMPLE.COM,
> Server not found in Kerberos database
> Jan 19 21:59:05 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: UNKNOWN_SERVER: authtime 1232423782,
> user5@STATION5.EXAMPLE.COM for host/station5@STATION5.EXAMPLE.COM,
> Server not found in Kerberos database
> Jan 19 21:59:05 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.6: UNKNOWN_SERVER: authtime 1232423782,
> user5@STATION5.EXAMPLE.COM for host/station5@STATION5.EXAMPLE.COM,
> Server not found in Kerberos database
> 
> #####after password entry when ssh from station6 to station5
> 
> Jan 19 21:59:37 station5 krb5kdc[1876](info): AS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.5: NEEDED_PREAUTH: user5@STATION5.EXAMPLE.COM
> for krbtgt/STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM, Additional pre-
> authentication required
> Jan 19 21:59:37 station5 krb5kdc[1876](info): AS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.5: NEEDED_PREAUTH: user5@STATION5.EXAMPLE.COM
> for krbtgt/STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM, Additional pre-
> authentication required
> Jan 19 21:59:37 station5 krb5kdc[1876](info): AS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.5: ISSUE: authtime 1232423977, etypes {rep=16
> tkt=16 ses=16}, user5@STATION5.EXAMPLE.COM for krbtgt/
> STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM
> Jan 19 21:59:37 station5 krb5kdc[1876](info): AS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.5: ISSUE: authtime 1232423977, etypes {rep=16
> tkt=16 ses=16}, user5@STATION5.EXAMPLE.COM for krbtgt/
> STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM
> Jan 19 21:59:37 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.5: ISSUE: authtime 1232423977, etypes {rep=16
> tkt=16 ses=16}, user5@STATION5.EXAMPLE.COM for host/
> station5.example.com@STATION5.EXAMPLE.COM
> Jan 19 21:59:37 station5 krb5kdc[1876](info): TGS_REQ (7 etypes {18 17
> 16 23 1 3 2}) 192.168.1.5: ISSUE: authtime 1232423977, etypes {rep=16
> tkt=16 ses=16}, user5@STATION5.EXAMPLE.COM for host/
> station5.example.com@STATION5.EXAMPLE.COM
> 
> 
> 
> ##### results of getprincs
> 
> K/M@STATION5.EXAMPLE.COM
> host/station5.example.com@STATION5.EXAMPLE.COM
> host/station6.example.com@STATION5.EXAMPLE.COM
> kadmin/admin@STATION5.EXAMPLE.COM
> kadmin/changepw@STATION5.EXAMPLE.COM
> kadmin/history@STATION5.EXAMPLE.COM
> kadmin/station5@STATION5.EXAMPLE.COM
> krbtgt/STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM
> root/admin@STATION5.EXAMPLE.COM
> user5@STATION5.EXAMPLE.COM
> 
> 
> #####following is my /etc/krb5.conf
> 
> [logging]
>  default = FILE:/var/log/krb5libs.log
>  kdc = FILE:/var/log/krb5kdc.log
>  admin_server = FILE:/var/log/kadmind.log
> 
> [libdefaults]
>  default_realm = STATION5.EXAMPLE.COM
>  dns_lookup_realm = false
>  dns_lookup_kdc = false
>  ticket_lifetime = 24h
>  forwardable = yes
> 
> [realms]
> STATION5.EXAMPLE.COM = {
>   kdc = 192.168.1.5:88
>   admin_server = 192.168.1.5:749
>  }
> 
> [domain_realm]
>  station5.example.com = STATION5.EXAMPLE.COM
>  station6.example.com = STATION5.EXAMPLE.COM
> 
> [kdc]
>  profile = /var/kerberos/krb5kdc/kdc.conf
> 
> [appdefaults]
>  pam = {
>    validate = true
>    debug = false
>    ticket_lifetime = 36000
>    renew_lifetime = 36000
>    forwardable = true
>    krb4_convert = false
>  }
> 
> ##### Following are the results of getprincs
> 
> Authenticating as principal root/admin@STATION5.EXAMPLE.COM with
> password.
> kadmin.local:  getprincs
> K/M@STATION5.EXAMPLE.COM
> host/station5.example.com@STATION5.EXAMPLE.COM
> host/station6.example.com@STATION5.EXAMPLE.COM
> kadmin/admin@STATION5.EXAMPLE.COM
> kadmin/changepw@STATION5.EXAMPLE.COM
> kadmin/history@STATION5.EXAMPLE.COM
> kadmin/station5@STATION5.EXAMPLE.COM
> krbtgt/STATION5.EXAMPLE.COM@STATION5.EXAMPLE.COM
> root/admin@STATION5.EXAMPLE.COM
> user5@STATION5.EXAMPLE.COM
> 
> 
> ############Following is my /var/kerberos/krb5kdc/kdc.conf
> 
> [kdcdefaults]
>  acl_file = /var/kerberos/krb5kdc/kadm5.acl
 dict_file = /usr/share/dict/words
 admin_keytab = /var/kerberos/krb5kdc/kadm5.keytab
 v4_mode = nopreauth

[realms]
STATION5.EXAMPLE.COM = {
  master_key_type = des3-hmac-sha1
  default_principal_flags = +preauth
#  supported_enctypes = des3-hmac-sha1:normal arcfour-hmac:normal des-
hmac-sha1:normal des-cbc-md5:normal des-cbc-crc:normal des-cbc-crc:v4
des-cbc-crc:afs3
 }



-- 
  Richard Silverman
  res@qoxp.net

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