[idu] dnsmasq: config improvements

* we are the authoritative DHCP server for all local networks
* filter bogus windows DNS queries
* don't respect local resolv.conf (pointing to localhost)
* increase cache size to 1000 entries

recipes-extra/dnsmasq/files/sysmocom-idu/dnsmasq.conf

@@ -4,6 +4,9 @@
 # as the long options legal on the command line. See
 # "/usr/sbin/dnsmasq --help" or "man 8 dnsmasq" for details.
 
+# we are the only (valid) DHCP server on the networks that we serve
+dhcp-authoritative
+
 # Change these lines if you want dnsmasq to serve MX records.
 # Only one of mx-host and mx-target need be set, the other defaults
 # to the name of the host  running dnsmasq.
@@ -28,7 +31,7 @@ bogus-priv
 # which can trigger dial-on-demand links needlessly.
 # Note that (amongst other things) this blocks all SRV requests, 
 # so don't use it if you use eg Kerberos.
-#filterwin2k
+filterwin2k
 
 # Change this line if you want dns to get its upstream servers from
 # somewhere other that /etc/resolv.conf 
@@ -44,7 +47,7 @@ bogus-priv
 # If you don't want dnsmasq to read /etc/resolv.conf or any other
 # file, getting its servers for this file instead (see below), then
 # uncomment this
-#no-resolv
+no-resolv
 
 # If you don't want dnsmasq to poll /etc/resolv.conf or other resolv
 # files for changes and re-read them then uncomment this.
@@ -272,7 +275,7 @@ dhcp-option=42,172.16.1.1
 #dhcp-leasefile=/var/lib/misc/dnsmasq.leases
 
 # Set the cachesize here.
-#cache-size=150
+cache-size=1000
 
 # If you want to disable negative caching, uncomment this.
 #no-negcache