Re: krb5 issues

[Ken Bass <kbass@kenbass.com>]

On 05/23/2016 11:21 AM, Ken Bass wrote:
> I enabled krb5 in my audisp-remote and audispd-remote reports "GSS-API 
> error sending token length" and fails to log remotely.
>
> If I reboot the destination auditd server AFTER the clients are 
> running it appears to work. But if I reboot any clients machine, 
> logging from that rebooted machine fails.
> I created my service principals using freeipa - all systems are clean 
> installs of Centos 7.2.
>
> For now, I disabled krb5, but that is not a good solution.

After disabling krb5 and rebooting the client servers several times I am 
seeing similar problems. I am seeing a dozen or so log file entries of

Too many connections from 10.10.10.10:39107 - rejected

I only have 2 clients and all I am doing is rebooting them. I tried 
increasing the tcp_listen_queue to 20 (from the default of 5) which made 
no difference.

I seem to have traced it to needing to specify the tcp_client_ports to 
60 rather than using whatever the default was. What would have been 
blocking this? And why only when the clients are rebooted second does it 
fail?

After changing this the Kerberos works, so I think the 'error sending 
token length' is basically the same message but in a different code path 
to indicate the connection is rejected / cannot write to the TCP socket.

Was the commented out ##tcp_client_ports parameter supposed to be 
changed by the end user? Was the defaults supposed to work?

On a related note, using krb5 causes a problem with selinux. Unless I 
disable it (or figure out a rule) auditd fails to start because it is 
denied permission to create /var/tmp/auditd_0 kerberos replay cache file.
Is there a rule or procedure to properly fix that?