On 04/07/2021 21:32, Simon Kelley wrote: > On 30/06/2021 10:40, Kevin Darbyshire-Bryant wrote: >> As an ‘experiment’ I tried switching from my own local ‘adblocking’ solution >> to using an upstream adblocking resolver, eg. cloudflare’s 1.1.1.2 or >> 1.1.1.3 service. >> >> The local adblock solution uses (multiple!) ‘—address/naughtydomain.foo/‘ >> lines that cause dnsmasq to return ’NXDOMAIN’ - fair enough. >> >> Cloudflare (& others I’ve tested) return ‘0.0.0.0’ or ‘::’ instead, not >> NXDOMAIN. With rebind protection enabled (--stop-dns-rebind), even with >> --rebind-localhost-ok I get log ’spam’ warning of possible rebind attacks >> due to the ‘0.0.0.0’ address response. >> >> I can turn ‘0.0.0.0’ into NXDOMAIN by using --bogus-nxdomain=0.0.0.0 and >> that works fine and stops the rebind warnings. However ‘::’ still gets >> through if an AAAA is specifically requested. There is no equivalent >> bogus-nxdomain for ipv6. >> >> The dnsmasq manpage (under —address) advised "Note that NULL addresses >> [0.0.0.0 & ::] normally work in the same way as localhost, so beware that >> clients looking up these names are likely to end up talking to themselves.” >> Ideally then 0.0.0.0 & :: would both be turned into NXDOMAIN. >> >> Should ‘0.0.0.0/32’ be excluded from the rebind checks/accepted by the >> ‘—rebind-localhost-ok’ option. It’s currently being caught by a ‘0.0.0.0/8’ >> check. >> > > I looked at the code that determines private addresses for --bogus-priv > and rebind: It's a bit unruly for IPv6, so I've rationalised things and > included :: and 0.0.0.0 in the --rebind-localhost-ok coverage, which at > least avoids the log spam. > > > I wonder if bogus-nxdomain should be extended to IPv6, or we could add > another option which is the equivalent of > > bogus-nxdomain=0.0.0.0,:: > > Or both. > > Simon. >
AT the least, bogus-nxdomain should be extended to IPv6, that would extend --ignore-address too, for free. In progress. Simon. _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
