IPv4 control socket binding failure with BIND 9.9.4-P1 on RHEL6
Jay Ford
jay-ford at uiowa.edu
Thu Dec 5 16:49:19 UTC 2013
I'm testing BIND 9.9.4-P1 on a RHEL6 system & am getting this log message:
/etc/named.conf:56: couldn't add command channel 127.0.0.1#953: address in use
That's with an rndc.key file in place & no "controls" config, which implies
TCP 953 on 127.0.0.1 & ::1.
Control via IPv6 (::1 port 953) works fine, but IPv4 doesn't:
% netstat -an -A inet | fgrep :953
% netstat -an -A inet6 | fgrep :953
tcp 0 0 ::1:953 :::* LISTEN
Even if I try to configure the controls to listen on a different port for
IPv6, such as:
controls {
inet ::1 port 954 allow { localhost; };
inet 127.0.0.1 allow { localhost; };
};
the IPv4 bind still fails, while the IPv6 bind works.
Interestingly, the bindings for the query ports (TCP & UDP 53 IPv4 & IPv6)
work fine, with just this under "options":
listen-on-v6 { "any"; };
This is all using BIND built from ISC source (not a RedHat package). Here's
the "named -V" output:
BIND 9.9.4-RedHat-9.9.4-P1_UIOWA.el6 (Extended Support Version)
<id:8f9657aa> built with '--host=x86_64-redhat-linux-gnu'
'--build=x86_64-redhat-linux-gnu' '--program-prefix=' '--prefix=/usr'
'--exec-prefix=/usr' '--bindir=/usr/bin' '--sbindir=/usr/sbin'
'--sysconfdir=/etc' '--datadir=/usr/share' '--includedir=/usr/include'
'--libdir=/usr/lib64' '--libexecdir=/usr/libexec'
'--sharedstatedir=/var/lib' '--mandir=/usr/share/man'
'--infodir=/usr/share/info' '--with-libtool' '--localstatedir=/var'
'--enable-threads' '--enable-ipv6' '--with-pic' '--disable-static'
'--disable-openssl-version-check' '--enable-rrl' '--with-gssapi=yes'
'--disable-isc-spnego'
'--with-docbook-xsl=/usr/share/sgml/docbook/xsl-stylesheets'
'--enable-fixed-rrset' 'build_alias=x86_64-redhat-linux-gnu'
'host_alias=x86_64-redhat-linux-gnu' 'CFLAGS= -O2 -g' 'CPPFLAGS=
-DDIG_SIGCHASE'
using OpenSSL version: OpenSSL 1.0.1e 11 Feb 2013
using libxml2 version: 2.7.6
RHEL6 has kernel variable net.ipv6.bindv6only set to 0, which might or might
not be related. BIND 9.8.5-P2 works correctly on a RHEL5 system which also
has it set to 0. There are some comments in some of the 9.9 release notes
about bindv6only, but I couldn't find anything specific to this situation.
Is this a configuration problem or something more in the bug category?
________________________________________________________________________
Jay Ford, Network Engineering Group, Information Technology Services
University of Iowa, Iowa City, IA 52242
email: jay-ford at uiowa.edu, phone: 319-335-5555
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