This is happening when my client and proxy are using the same DNS server. In this case, a local OS X Server which forwards to my ISP’s DNS servers. As far as I can tell Google’s DNS isn’t in the equation any more. Even so, if I run a `dig watch` on the domain, it happily cycles through a pool of IPs apparently at random. > On 29 Oct 2015, at 3:46 PM, Amos Jeffries <squid3@xxxxxxxxxxxxx> wrote: > > On 29/10/2015 1:16 p.m., Dan Charlesworth wrote: >> It looks like there’s certain hosts that are designed to load balance (or something) between a few IPs, regardless of geography. >> >> For example pbs.twimg.com resolves to wildcard.twimg.com which returns two different IPs each time, from a pool of 5–6, at random. Basically rolling the dice whether the client and the proxy are going to get the same IPs at the same time. >> >> What is one to do about that? > > The same thing. Ensuring that the proxy and the clients are using the > same DNS server. > > The reasoning goes like so: > * some client does a DNS fetch causing the result to be cached in *that* > server. > * then the proxy repeats the query and gets the DNS cached result. > * those results should match 99% of the time even if the domain DNS is > playing tricks. > > This falls down with the Google DNS because "8.8.8.8" is not one server > but an entire farm of servers spread aroudn the globe. The two > consecutive queries done often go to different physical servers. > > You can of course configure 8.8.8.8 to be an upstream resolver for your > local DNS server if you think that is a good idea. The key think is > having the same local-end DNS cache being used by the clients and Squid. > > > NP: these problems do not exist for forward proxies. Only for traffic > hijacking interceptor proxies. > > Amos > > _______________________________________________ > squid-users mailing list > squid-users@xxxxxxxxxxxxxxxxxxxxx > http://lists.squid-cache.org/listinfo/squid-users _______________________________________________ squid-users mailing list squid-users@xxxxxxxxxxxxxxxxxxxxx http://lists.squid-cache.org/listinfo/squid-users
