[Samba] bind9 lockup problem

[Arnaud FLORENT]

Hi everyone and best wishes for 2023


I think i'm facing the bind 9 DLZ lockup problem described here:

https://wiki.samba.org/index.php/BIND9_DLZ_DNS_Back_End#The_Lockup_Problem


running samba 4.16 AD on ubuntu 20.04 with bind 9.16.15

there are about 500 computers on the network.


quickly after bind restart, DNS response delay increase and reach client 
timeout (like host or dig on samba host) and named is long to stop.


if i disable dlz config on named, there are no dns outage but AD is broken.


so we setup an external dns server forwarding only query to the AD 
domain zone as suggested in wiki.


i have a few questions:

- before running samba 4.3 on ubuntu 16.04  with bind 9.10 , i got no 
outage. Does this problem appear on specific bind or samba version?

- is there a metric or log  i can check in samba or named stats 
(returned by running rndc stats) to be sure this is the lockup problem 
described in wiki?

- is there a way to reproduce this problem with a script from only one 
dns client?

- is there alternative solution (than running external dns server)

- is a fix in bind or samba planned?


Thanks,




-- 
Arnaud FLORENT
IRIS Technologies