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On 14/02/15 20:00, Nikolay P wrote: > Thank you. > > Well it looks like dnsmasq does not cache. When I send SIGUSR1 to > dnsmasq (with log-queries option enabled) it returns list of cache > which consists of one entry - 127.0.0.1 (flags 4FRI H). This is > despite the fact that I performed dozen of queries just before. > > Log file looks like: > > query[A] host.domain from 127.0.0.1 forwarded host.domain to > 10.0.0.1 reply host.domain is 10.0.10.10 query[A] host.domain from > 127.0.0.1 forwarded host.domain to 10.0.0.1 reply host.domain is > 10.0.10.10 query[A] host.domain from 127.0.0.1 forwarded > host.domain to 10.0.0.1 reply host.domain is 10.0.10.10 > > 10.0.0.1 is my internal DNS server (it is authoritative for domain > "domain") > > Is there known list of issues which can force dnsmasq not to cache > replies? Otherwise I have no idea where to dig. If the time-to-live value in the replies for host.domain is zero or only a few seconds, then the reply will either not be cached, or thrown out before you get around to re-querying it. Use "dig" to make the test queries, and it will tell you the TTL values. (It's also possible to disable caching in dnsmasq by configuration. You're unlikely to have done that by accident) Cheers, Simon. > > > ----- Original Message ----- From: "/dev/rob0" <r...@gmx.co.uk> > To: dnsmasq-discuss@lists.thekelleys.org.uk Sent: Thursday, > February 12, 2015 10:13:40 PM GMT -05:00 US/Canada Eastern Subject: > Re: [Dnsmasq-discuss] What if external DNS unreachable or timed > out > > On Thu, Feb 12, 2015 at 08:43:20PM -0500, Nikolay P wrote: >> I am wondering what will happen if none of the external DNS >> servers are reachable or suddenly (for any reason) a DNS query to >> external servers timed out. Will Dnsmasq reply to the client's >> request from cache? Assume that this particular query is >> performed frequently and it should be in Dnsmasq cache. > > If the record is cached, dnsmasq is not going to ask an upstream > nameserver. If a query is made to an upstream nameserver, that > means the record is NOT in the cache. > > Then if the upstream query times out or otherwise fails, that's > what dnsmasq will tell the client. > >> So, will the Dnsmasq reply to the client's request from cache if >> none of the external servers replied? > > No, it wasn't cached. > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCAAGBQJU391GAAoJEBXN2mrhkTWiMQYP/Anapo7LXImykuh7EdzkVYlj Fa7LrmR9aEpI6S0mhPDd3zx37BUquT9xTIhhXSzOwVWuR/eCf8pJx3vq8PHhaQiw OnvMS9jPXk2fLUFEoB8QEs022nKaKokrJMUMnpGN8GkhPSpge4oZcWJCd122lKHm 5HcJvGiMo9OEs4w8eVpt1rcOVWyjBYh4N7XUhCiKDkAAW3mgwxOaaVjfZNVbDDKN arPYWEpUpGs1F8r6l3LWhP0gTzaiBkqCd/L8+PQ8Yl8nMY17Ugh8l/NcYaH0iQ11 BRUJwLCcG2gCgKWVHH8YnXVqv/hESE8zdD/DVe8NJcLzMAV45GCvp951COgJazJg h/xg+T/N4CIN/BDUGrK4GMr7s7eptbfYzYV2VcvNZhqMlPSHY1mcfxlEMdBSGmKS SuJFxqlCzW4/i9EoyPGT7uhSCkjmYOG+SwMqa3GMQAKBdEXe94hTtCV/sHuuD1Ln T6R5r5vkBWVhUX3V8/BwoTSI/jDzqJUNGVNGCfO8McphjzbrX8GwMMtt3d2z+oZK D425KiCSagv44z/rFdijlIIjApbuIFzoalsuPfBBXgVetS1DL1k0ounAxCYPJxSx qdfA+y6ViIskIn1CD6JdfitOOqBX9JeW5M1ehn8ozr/WxDUFF3BYU5qGL+p1RUfL 3zr7pYGjwESyS4G1GRhY =wpl0 -----END PGP SIGNATURE----- _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
