How to fix the Active Directory Authentication Issue with Ubuntu 16.04 in AWS [closed]

Question

While trying to manually join a Linux Instance of Ubuntu 16.04 in AWS Manged Active Directory using the tutorial https://docs.aws.amazon.com/directoryservice/latest/admin-guide/join_linux_instance.html, the authentication to the realm succeeded, but after that I am getting this error while trying to join the UBuntu 16.04 instance to AD:

Couldn't authenticate to active directory: SASL(-1): generic failure: GSSAPI Error: An invalid name was supplied (Success)
adcli: couldn't connect to ad.nettracer.aero domain: Couldn't authenticate to active directory: SASL(-1): generic failure: GSSAPI Error: An invalid name was supplied (Success)
! Insufficient permissions to join the domain
realm: Couldn't join realm: Insufficient permissions to join the domain

however, the same is working for CentOS.

Is there is anything wrong happens from my end?

Answer 1

I have had the same issue with joining my Ubuntu 16.04 machine and all I had to do to resolve the problem is set the rdns flag to false in the krb5.conf as shown below:

/etc/krb5.conf

[libdefaults]
 dns_lookup_realm = false
 ticket_lifetime = 24h
 renew_lifetime = 7d
 forwardable = true
 rdns = false
# default_realm = EXAMPLE.COM
 default_ccache_name = KEYRING:persistent:%{uid}

Once you have added the line, you can join the machine to the domain by using the command:

sudo realm join -U [email protected] example.com --verbose