[Dnsmasq-discuss] dnsmasq not vending - replying with "Destination unreachable (Port unreachable)" until restarting the service

Arek Dreyer arek at arekdreyer.com
Thu Apr 15 22:02:54 BST 2010


Hi - I'm running dnsmasq on a Mac OS X Server 10.6.3 build 10D673

I'm using dnsmasq solely to control which AD DCs my Mac OS X clients will try to use.

Things seem fine until clients start receiving "Destination unreachable (Port unreachable)"
rather than a DNS answer.

Here's a screenshot from a wireshark capture: http://drp.ly/P8LcF

Stopping and starting the dnsmasq service fixes the issue. Any suggestions?

/var/log/dnsmasq.log is full of entries like this:
Apr 15 11:30:33 dnsmasq[99]: query[SOA] local from 127.0.0.1
Apr 15 11:30:33 dnsmasq[99]: forwarded local to 131.193.68.142
Apr 15 11:30:35 dnsmasq[99]: query[SOA] local from 127.0.0.1
Apr 15 11:30:35 dnsmasq[99]: forwarded local to 131.193.68.142
Apr 15 11:30:52 dnsmasq[99]: query[SOA] local from 127.0.0.1
Apr 15 11:30:52 dnsmasq[99]: forwarded local to 131.193.68.142
Apr 15 11:30:56 dnsmasq[99]: query[SOA] local from 127.0.0.1
Apr 15 11:30:56 dnsmasq[99]: forwarded local to 131.193.68.142
Apr 15 11:30:57 dnsmasq[99]: query[SOA] local from 127.0.0.1
Apr 15 11:30:57 dnsmasq[99]: forwarded local to 131.193.68.142
Apr 15 11:31:09 dnsmasq[99]: query[SOA] local from 127.0.0.1
Apr 15 11:31:09 dnsmasq[99]: forwarded local to 131.193.68.142
Apr 15 11:31:09 dnsmasq[99]: query[SOA] local from 127.0.0.1
Apr 15 11:31:09 dnsmasq[99]: forwarded local to 131.193.68.142
Apr 15 11:31:39 dnsmasq[99]: query[SOA] local from 127.0.0.1
Apr 15 11:31:39 dnsmasq[99]: forwarded local to 131.193.68.142

This is how the dnsmasq service is running:
/usr/local/sbin/dnsmasq --keep-in-foreground --log-queries --log-facility=/var/log/dnsmasq.log

The non-commented lines in 
/etc/dnsmasq.conf are:
domain-needed
log-queries
no-poll
no-resolv
server=131.193.68.142
srv-host=_kerberos._tcp.ad.uic.edu,uic-cc-dc1.ad.uic.edu,88,0,100
srv-host=_kerberos._tcp.ad.uic.edu,uic-cc-dc2.ad.uic.edu,88,0,100
srv-host=_kerberos._tcp.ad.uic.edu,uic-cc-dc3.ad.uic.edu,88,0,100
srv-host=_kerberos._udp.ad.uic.edu,uic-cc-dc1.ad.uic.edu,88,0,100
srv-host=_kerberos._udp.ad.uic.edu,uic-cc-dc2.ad.uic.edu,88,0,100
srv-host=_kerberos._udp.ad.uic.edu,uic-cc-dc3.ad.uic.edu,88,0,100
srv-host=_kpasswd._tcp.ad.uic.edu,uic-cc-dc1.ad.uic.edu,464,0,100
srv-host=_kpasswd._tcp.ad.uic.edu,uic-cc-dc2.ad.uic.edu,464,0,100
srv-host=_kpasswd._tcp.ad.uic.edu,uic-cc-dc3.ad.uic.edu,464,0,100
srv-host=_kpasswd._udp.ad.uic.edu,uic-cc-dc1.ad.uic.edu,464,0,100
srv-host=_kpasswd._udp.ad.uic.edu,uic-cc-dc2.ad.uic.edu,464,0,100
srv-host=_kpasswd._udp.ad.uic.edu,uic-cc-dc3.ad.uic.edu,464,0,100
srv-host=_ldap._tcp.ad.uic.edu,uic-cc-dc1.ad.uic.edu,389,0,100
srv-host=_ldap._tcp.ad.uic.edu,uic-cc-dc2.ad.uic.edu,389,0,100
srv-host=_ldap._tcp.ad.uic.edu,uic-cc-dc3.ad.uic.edu,389,0,100

/etc/hosts:
##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1       localhost
255.255.255.255 broadcasthost
::1             localhost 
fe80::1%lo0     localhost
131.193.68.142  ad.uic.edu

/etc/resolv.conf (which I know is just a snapshot in Mac OS X):
#
# Mac OS X Notice
#
# This file is not used by the host name and address resolution
# or the DNS query routing mechanisms used by most processes on
# this Mac OS X system.
#
# This file is automatically generated.
#
search ad.uic.edu
nameserver 127.0.0.1




Thanks!

Arek Dreyer, Dreyer Network Consultants, Inc.
Apple Certified System Administrator
arek at arekdreyer.com  773-251-8931







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