Kerberos authentication from MacOS Monterey to access Hadoop Web UI post cluster Kerberization

[#1]

Hi Team,

I want to setup kerberos client in my Mac Laptop having MacOS Monterey (version 12.6.5). I have put the krb5.conf file at below paths.
/etc/krb5.conf
/Library/Preferences/edu.mit.kerberos

But when I try to run kinit, i get gelow error.
--
kinit -kt /Users/banshidhar_sahoo/Desktop/POC_KEYTAB/test.headless.keytab [email protected]
kinit: krb5_get_init_creds: unable to reach any KDC in realm EXAMPLE.COM, tried 0 KDCs
--

I have also set the ENV Variable as below:
KRB5_CONFIG=/etc/krb5.conf

But getting same error while doing kinit.

Can you please suggest how to point to krb5.conf so that it can reach out to the correct kdc server.

Regards,
Banshi.

[#2]

@banshidhar_saho I am assuming you are not using @EXAMPLE.COM.   Have you confirmed that your client (mac os) has network and dns connectivity with the KDC Host?

There's a few things you must do to configure it properly:

• Ensure the Kerberos client libraries are installed on that host 
• Your on-prem krb5.conf file must be copied to the client host.
  • The sections [realms] and [domain_realm] are especially important to solve your issue.
• Ensure that the hostname of your KDC can be resolved from the client (you can test it with nslookup and/or ping). This must work correctly for Kerberos to work. If there's no integrated DNS you will have to add entries to your /etc/hosts file to ensure the resolution is correct.
• Ensure that any firewalls are configured correctly to open ports between your application and your on-prem environment:
  • Open all the ports required for the client to communicate with the KDC (typically, ports 88 UDP and 88 TCP)

[#3]

Hi @steven-matison You are right. I have replaced actual REALM with EXAMPLE.COM while posting. 

I have checked connectivity using "nc -zv" and "ping" command. Connectivity is fine.

====

nc -zv <kdc_server_VIP> <KDC_Port>
Connection to xxxxxxxx port xxxxxx [tcp/sqlexec] succeeded!

====

--- <kdc_server_VIP> ping statistics ---
13 packets transmitted, 12 packets received, 7.7% packet loss

====

"kinit: krb5_get_init_creds: unable to reach any KDC in realm EXAMPLE.COM, tried 0 KDCs"

By seeing the above error, I feel it's not able to locate the krb5.conf file.

When we run kinit command, is it referring to /etc directory for krb5.conf file or some other location in Mac machine?

Regards,

Banshi.

[#4 · Accepted solution]

Hi @steven-matison

The issue got fixed after making below 2 changes in /etc/krb5.conf file

1. Issue was a include line in my /etc/krb5.conf file which was not valid.

Removed below from /etc/krb5.conf
"includedir /etc/krb5.conf.d/"

2. On macOS the default client does not fall back to TCP. In krb5.conf prefix kdc value with tcp/ to force the client to use TCP if your corporate network blocks UDP.
kdc = tcp/kdc.example.com:88

Regards,

Banshi.