[Samba] Linux Servers in an AD Domain with Multiple Windows Domain Controllers

[Robinson, Eric]

> -----Original Message-----
> From: Marc Muehlfeld [mailto:samba at marc-muehlfeld.de] 
> Sent: Saturday, May 25, 2013 3:31 PM
> To: Robinson, Eric
> Cc: samba at lists.samba.org
> Subject: Re: [Samba] Linux Servers in an AD Domain with 
> Multiple Windows Domain Controllers
> 
> Hello Eric,
> 
> Am 25.05.2013 18:29, schrieb Robinson, Eric:
> > We have three Windows domain controllers in our AD domain. They are
>  > DC01, DC02, and DC03. We have Linux (RHEL5 and 6) servers 
> in the  > domain as well. The Linux servers are working fine 
> with AD. However,  > they are currently configured in 
> krb.conf and krb5.conf to use only  > DC01 for AD domain 
> controller. if DC01 is down, Linux servers cannot  > 
> authenticate. How do we configure the Linux servers to use 
> multiple  > domain controllers for AD, so if DC01 is down 
> everything continues  > to work on the Linux side?
> 
> I saw, that you asked that question already 1.5 years ago on 
> this list:
> http://markmail.org/message/slugpbka33ap4ima
> 
> Didn't the two suggestions from Marcel and Andrew work? If 
> not, what were the problems with them? Then maybe we find a 
> way to get it work.
> 
> Regards,
> Marc
>

Hi Marc -- Thanks very much for following up on this. I did try Marcel and Andrew's suggestions (see below) but it did not work. When server DC01 is down, Windows users can still login fine, but when I try to ssh to a Linux box, the login hangs for a long time or forever. Also, Marcel and Andrew did not address my follow-up question about the krb.conf file. They only mentioned the krb5.conf file.

For reference, my krb.conf looks like this... 

MYCHARTS.MD     dc01.mycharts.md:88
MYCHARTS.MD     dc01.mycharts.md:749 admin server

My krb5.conf looks like the following... note the second entry for the DC named TS04. 

[logging]
 default = FILE:/var/log/krb5libs.log
 kdc = FILE:/var/log/krb5kdc.log
 admin_server = FILE:/var/log/kadmind.log

[libdefaults]
 default_realm = MYCHARTS.MD
 dns_lookup_realm = true
 dns_lookup_kdc = true

[realms]
 MYCHARTS.MD = {
  kdc = dc01.mycharts.md:88
  kdc = ts04.mycharts.md:88
  admin_server = dc01.mycharts.md:749
  kpasswd_server = dc01.mycharts.md:464
  kpasswd_protocol = SET_CHANGE
  #default_domain = example.com
 }

[domain_realm]
 *.mycharts.md = MYCHARTS.MD
 .mycharts.md = MYCHARTS.MD

[kdc]
 profile = /var/kerberos/krb5kdc/kdc.conf

[appdefaults]
 pam = {
   debug = false
   ticket_lifetime = 36000
   renew_lifetime = 36000
   forwardable = true
   krb4_convert = false
 }

--Eric




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