Hi Bilal,

Good to hear you've pin-pointed the problem. I'm not one hundred percent sure 
on all the answers to your questions, but I'll throw in my 10 cents.. It's all 
a learning curve!

I've just created a new computer account using msktuil and I specified the SPN 
as HTTP/FuNnYName.{domain}. Checking ADSI showed that the SPN was entered: 
HTTP/funnyname.{domain}. It was converted into lowercase.

With regards to the UPN, it depends on how it's being used. By default you 
won't be using it I believe if you are just using it for the standard kerb 
authentication.. However, I was playing around with the squid_kerb_ldap 
external acl the other day and my experience was that a UPN was required - but 
not with the UPN specified as HTTP... Do a search on the list for my problem 
with it (post is titled 'Squid_ldap_kerb make'). Not exactly and answer but my 
own experience..

Re: SPN attribute and realms - I'm not sure on this.. Other than the way a 
computer account and user account differs in authenticating Kerberos.

As for the multiple SPNs in one account... That's up to you. I haven't tried it 
but I guess you could do it. As you know you can authenticate against an 
account providing there is an SPN... Is there a chance your keytab would get 
out of sync for either? If it broke both wouldn't work..

Nick




On 21/04/2010 11:36, "GIGO ." <[email protected]> wrote:




Dear Markus/Nick/All,

After a great struggle and help (i got from you people)i was managed to resolve 
the issue however i have few confusions which i wish you to ask please.


1. First of all I traced down my problem to SPN Names casesensitivity the case 
for ServicePrincipalName attribute as seen through ADSIEDIT.msc tool was 
different from the value my klist -ke was showing.



According to ASIedit.msc:


servicePrincipalName == HTTP/squidlhrtest.v.local
userPrinciapalName == HTTP/[email protected]

Where as klisting the SPN as stored in my keytab:
2 HTTP/[email protected] (DES cbc mode with CRC-32)
2 HTTP/[email protected] (DES cbc mode with RSA-MD5)
2 HTTP/[email protected] (ArcFour with HMAC/md5)

After diagnosing the problem i tried recreation of keytab/spn through msktutil 
utility however in no benefit. But Then i changed my hostname(squidmachines') 
all to lowercase and recreated the keytab and it worked. I confirmed that it 
matched the one as stored in the Active Directory. kerberos/negotiate was 
working. Although i have studied that microsoft spn is case insensitive but 
does this also mean that microsoft will always store spn in lower case no 
matter how you have given name in your msktutil command?


Second thing is that what is the role of upn here? I mean why a upn is required 
when created SPN with computer objects? I can understand that its some kind of 
linkage but i am not sure and clear about the purpose ?


Also why SPNattribute has no realm name appended in the output while upn has a 
realm name appended in the output when seeing it through ADSIEDIT.msc.


Another question is that as i am using SARG configured with Apache i am looking 
forward to SSO apache also with kerberos. Now the keytab/spn for squid sso is 
already here created as :

msktutil -c -b "CN=COMPUTERS" -s HTTP/squidlhrtest.v.local -h 
squidlhrtest.v.local -k /etc/squid/HTTP.keytab --computer-name squid-http --upn 
HTTP/squidlhrtest.v.local --server vdc.v.local --verbose

Right now to my understanding a keytab can have keys from multiple services so 
this means that i can have the same keytab used for squid & Apache both ?  For 
example i think the following command will append the keytab file with the 
following new keys. I guess that only computer-name is to be changed and the 
rest of the same command will do as far as the keytab creation is concerned. 
(apache specific settings is a seperate story which is definately out of scope 
here)

The command to my understanding which will append keys to be used by Apache:

msktutil -c -b "CN=COMPUTERS" -s HTTP/squidlhrtest.v.local -h 
squidlhrtest.v.local -k /etc/squid/HTTP.keytab --computer-name apache-http 
--upn HTTP/squidlhrtest.v.local --server vdc.v.local --verbose


But why not apache and squid should share a single keytab? as after all they 
are both HTTP in the end. Isnt creating a seperate key/spn for apache be 
redundant or it is must?



Another somewhat similar question is that My active Directory setup has a 
single forest with one Parent A wand two childs B and childs C. The internet 
users are only in childs A and B. What would be the way to handle SSO. I have 
not much clarity can anybody please advice? .......................How Would i 
be pointing to the multiple realms? would i b duplicate exact setup which i 
have done for 1 domain and somehow(i am unclear) somehow update squid 
accordingly?




Please i would be real thankful to all of you for guidance/help.



best regards,

Bilal Aslam
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