[Samba] Samba keeps crashing when in AD mode due to mitkdc exiting.

[Matthew Schumacher]

Hello All,

I have a number of samba servers acting like RODC controllers and every 
few days samba exits because the MIT KDC Daemon dies with exit status 11:

[2022/06/04 21:14:29.561323,  0] 
../../source4/dsdb/kcc/scavenge_dns_records.c:523(dns_delete_tombstones)
   dns_delete_tombstones: Failed to delete dns node
   kccsrv_dns_zone_tombstone_deletion: DNS tombstone deletion failed: 
NT_STATUS_INTERNAL_ERRORkccsrv_periodic_run: 
kccsrv_dns_zone_tombstone_scavenging failed - NT_STATUS_INTERNAL_ERROR
: Address family not supported by protocol The MIT KDC daemon died with 
exit status 11
: Address family not supported by protocol task_server_terminate: 
task_server_terminate: [mitkdc child process exited]
[2022/06/05 20:18:54.520080,  0] 
../../source4/samba/server.c:391(samba_terminate)
   samba_terminate: samba_terminate of samba 714: mitkdc child process 
exited

in the mit_kdc.log I see:

Jun 05 20:18:54 host.ad.domain.net krb5kdc[753](info): TGS_REQ (5 etypes 
{aes256-cts-hmac-sha1-96(18), aes128-cts-hmac-sha1-96(17), 
DEPRECATED:arcfour-hmac(23), DEPRECATED:arcfour-hmac-exp(24), 
UNSUPPORTED:(-135)}) 172.23.77.6: PROCESS_TGS: authtime 0, etypes 
{rep=UNSUPPORTED:(0)} <unknown client> for 
krbtgt/ad.domain.net at ad.domain.net, No matching key in entry
Jun 05 20:18:54 host.ad.domain.net krb5kdc[753](info): closing down fd 21

I'm using samba-4.16.1 and krb5-1.19.3.  Any thoughts on how to debug 
this issue so that I can report a bug to at least keep it running?

I can compile an alternate kerberos daemon and rebuild samba against it, 
but it's my understanding that AD mode only works with MIT kerberos.

schu