[Dnsmasq-discuss] Block PTR queries for local IPs being sent upstream

Ed W lists at wildgooses.com
Sun Dec 11 19:00:13 GMT 2011


Hi, I have setup my DHCP to allocate to 192.168.111.0/24.  However, I
notice queries from my ipad for various PTR records for this range
getting forwarded to my upstream DNS, eg:

Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: query[PTR]
b._dns-sd._udp.225.177.159.10.in-addr.arpa from 192.168.111.137
Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: forwarded
b._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.8.8
Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: forwarded
b._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.4.4
Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: query[PTR]
db._dns-sd._udp.225.177.159.10.in-addr.arpa from 192.168.111.137
Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: forwarded
db._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.8.8
Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: forwarded
db._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.4.4
Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: query[PTR]
r._dns-sd._udp.225.177.159.10.in-addr.arpa from 192.168.111.137
Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: forwarded
r._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.8.8
Dec 11 18:25:55 localhost daemon.info dnsmasq[32485]: forwarded
r._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.4.4


I try and block these using:

   server=/111.168.192.in-addr.arpa/127.0.0.1

But nothing changes.  So I try:

   server=/111.168.192.in-addr.arpa/127.0.0.2

Now I see a bunch of repeated forwarding requests that look like dnsmasq
retries several times (but fails since obviously nothing listening).

I'm still left with the ipad inexplicably doing some more queries for
some 10.x.x.x ips... No idea how/why, can't see this IP anywhere on my
network:

Dec 11 18:28:08 localhost daemon.info dnsmasq[590]: query[PTR]
dr._dns-sd._udp.225.177.159.10.in-addr.arpa from 192.168.111.137
Dec 11 18:28:08 localhost daemon.info dnsmasq[590]: forwarded
dr._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.8.8
Dec 11 18:28:08 localhost daemon.info dnsmasq[590]: forwarded
dr._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.4.4
Dec 11 18:28:08 localhost daemon.info dnsmasq[590]: query[PTR]
lb._dns-sd._udp.225.177.159.10.in-addr.arpa from 192.168.111.137
Dec 11 18:28:08 localhost daemon.info dnsmasq[590]: forwarded
lb._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.8.8
Dec 11 18:28:08 localhost daemon.info dnsmasq[590]: forwarded
lb._dns-sd._udp.225.177.159.10.in-addr.arpa to 8.8.4.4



How can I tell dnsmasq that it's effectively authoritive for reverse
lookups for private IP ranges and prevent upstream lookups?  I do have
"bogus-priv" set.  Dnsmasq-1.58

(Note I have a dialup network, the extra dns queries are a problem for
minimising costs)

Thanks

Ed W



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