Maintained by: NLnet Labs

[Unbound-users] Resource temporarily unavailable and query problem with unbound

Sebastian Nickel - Hetzner Online AG
Mon Nov 8 17:05:09 CET 2010


Hello,
we are using unbound in our environment. I recently looked into the
logfile and found many of those lines:

"""
[1289226893] unbound[5117:1] notice: sendmsg failed: Resource
temporarily unavailable
[1289226893] unbound[5117:1] notice: remote address is xxx.xxx.xxx.xxx
port 53588
"""

What is the meaning of those lines? Is there perhaps a performance
issue?


Some infos about unbound (it is the debian squeeze package):

Version 1.4.6
linked libs: libev 3.9 (it uses epoll), ldns 1.4.0, OpenSSL 0.9.8o 01
Jun 2010
linked modules: validator iterator
configured for x86_64-pc-linux-gnu on Sun Aug 15 22:32:30 UTC 2010 with
options: '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=
${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=
${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var'
'--libexecdir=${prefix}/lib/unbound' '--disable-maintainer-mode'
'--disable-dependency-tracking' '--disable-rpath'
'--with-chroot-dir=/var/lib/unbound'
'--with-pidfile=/var/run/unbound.pid' '--with-libevent'
BSD licensed, see LICENSE in source package for details.
Report bugs to unbound-bugs at nlnetlabs.nl



Another problem I have is a "SERVFAIL" with the domain "imgw.pl".

I do this query with dig on our unbound host (with allow_snoop option
set):

$> dig @localhost +trace imgw.pl

and get:
"""
; <<>> DiG 9.6-ESV-R1 <<>> +trace @localhost imgw.pl
; (1 server found)
;; global options: +cmd
.			518399	IN	NS	a.root-servers.net.
.			518399	IN	NS	h.root-servers.net.
.			518399	IN	NS	b.root-servers.net.
.			518399	IN	NS	d.root-servers.net.
.			518399	IN	NS	e.root-servers.net.
.			518399	IN	NS	l.root-servers.net.
.			518399	IN	NS	f.root-servers.net.
.			518399	IN	NS	i.root-servers.net.
.			518399	IN	NS	j.root-servers.net.
.			518399	IN	NS	g.root-servers.net.
.			518399	IN	NS	c.root-servers.net.
.			518399	IN	NS	m.root-servers.net.
.			518399	IN	NS	k.root-servers.net.
;; Received 500 bytes from 127.0.0.1#53(127.0.0.1) in 0 ms

pl.			172800	IN	NS	a-dns.pl.
pl.			172800	IN	NS	c-dns.pl.
pl.			172800	IN	NS	d-dns.pl.
pl.			172800	IN	NS	e-dns.pl.
pl.			172800	IN	NS	f-dns.pl.
pl.			172800	IN	NS	g-dns.pl.
pl.			172800	IN	NS	h-dns.pl.
pl.			172800	IN	NS	i-dns.pl.
;; Received 399 bytes from 193.0.14.129#53(k.root-servers.net) in 6 ms

imgw.pl.		86400	IN	NS	krgw1.imgw.pl.
imgw.pl.		86400	IN	NS	wagw1.imgw.pl.
;; Received 97 bytes from 195.80.237.162#53(e-dns.pl) in 40 ms

;; connection timed out; no servers could be reached
Segmentation fault
"""

If I drop the "+trace" option I just receive a "SERVFAIL" answer.


If I do this on my local machine (no unbound):

"""
; <<>> DiG 9.5.1-P2.1 <<>> +trace imgw.pl
;; global options:  printcmd
.			84891	IN	NS	c.root-servers.net.
.			84891	IN	NS	a.root-servers.net.
.			84891	IN	NS	g.root-servers.net.
.			84891	IN	NS	f.root-servers.net.
.			84891	IN	NS	e.root-servers.net.
.			84891	IN	NS	l.root-servers.net.
.			84891	IN	NS	m.root-servers.net.
.			84891	IN	NS	j.root-servers.net.
.			84891	IN	NS	b.root-servers.net.
.			84891	IN	NS	h.root-servers.net.
.			84891	IN	NS	d.root-servers.net.
.			84891	IN	NS	i.root-servers.net.
.			84891	IN	NS	k.root-servers.net.
;; Received 449 bytes from 192.168.2.1#53(192.168.2.1) in 43 ms

pl.			172800	IN	NS	c-dns.pl.
pl.			172800	IN	NS	f-dns.pl.
pl.			172800	IN	NS	e-dns.pl.
pl.			172800	IN	NS	i-dns.pl.
pl.			172800	IN	NS	d-dns.pl.
pl.			172800	IN	NS	h-dns.pl.
pl.			172800	IN	NS	a-dns.pl.
pl.			172800	IN	NS	g-dns.pl.
;; Received 397 bytes from 192.33.4.12#53(c.root-servers.net) in 61 ms

imgw.pl.		86400	IN	NS	krgw1.imgw.pl.
imgw.pl.		86400	IN	NS	wagw1.imgw.pl.
;; Received 97 bytes from 194.0.1.2#53(h-dns.pl) in 61 ms

imgw.pl.		3600	IN	A	195.187.86.14
imgw.pl.		3600	IN	A	195.187.86.13
;; Received 71 bytes from 212.160.142.68#53(krgw1.imgw.pl) in 70 ms
"""


Does anybody know why unbound has problems with this domain?


Thanks for any answers...


Best regards,
Nick