[Samba] samba_dnsupdate timeout

Andrea Venturoli ml at netfence.it
Fri Dec 10 08:46:59 UTC 2021


Hello.

This is a non-problem, as it doesn't seem to produce any illness; it's 
just spamming the logs with warnings and I'm a curious type...

I'm running 4.13.14 as an AD DC in a FreeBSD 12.2 jail.
Recently I started seeing the following, several times in a day:

> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898236,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate: Traceback (most recent call last):
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898341,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:   File "/usr/local/sbin/samba_dnsupdate", line 298, in check_dns_name
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898367,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:     ans = check_one_dns_name(normalised_name, d.type, d)
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898392,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:   File "/usr/local/sbin/samba_dnsupdate", line 275, in check_one_dns_name
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898416,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:     return resolver.resolve(name, name_type)
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898440,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:   File "/usr/local/lib/python3.8/site-packages/dns/resolver.py", line 900, in query
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898464,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:     timeout = self._compute_timeout(start, lifetime)
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898487,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:   File "/usr/local/lib/python3.8/site-packages/dns/resolver.py", line 799, in _compute_timeout
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898517,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:     raise Timeout(timeout=duration)
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898541,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate: dns.exception.Timeout: The DNS operation timed out after 15.015800714492798 seconds
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898566,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate: 
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898590,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate: During handling of the above exception, another exception occurred:
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898613,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate: 
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898637,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate: Traceback (most recent call last):
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898661,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:   File "/usr/local/sbin/samba_dnsupdate", line 848, in <module>
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898685,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:     elif not check_dns_name(d):
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898710,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:   File "/usr/local/sbin/samba_dnsupdate", line 300, in check_dns_name
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898742,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate:     raise Exception("Timeout while waiting to contact a working DNS server while looking for %s as %s" % (d, normalised_name))
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.898767,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
> Dec 10 09:26:35 xxxxx samba[68685]:   /usr/local/sbin/samba_dnsupdate: Exception: Timeout while waiting to contact a working DNS server while looking for A dc1.ad.xxxx.netfence.it 192.168.128.2 as dc1.ad.xxxx.netfence.it.
> Dec 10 09:26:35 xxxxx samba[68685]: [2021/12/10 09:26:35.916175,  0] ../../source4/dsdb/dns/dns_update.c:86(dnsupdate_nameupdate_done)

I find this strange for several reason:
_ I've only got one fileserver and two clients here: all have a fixed IP 
address, so why samba_dnsupdate is called in the first place?
_ samba_dnsupdate is running on the DC here, so how can it timeout 
speaking to itself???
_ obiously name resolution works on that DC ("host 
dc1.ad.xxxx.netfence.it" gives 192.168.128.2 in no time);
_ I also added "allow dns updates=disabled" to smb.conf, but nothing 
changed.

  bye & Thanks
	av.



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