On 11/11/13 19:12, Tim wrote:
That'd be HTTP caching. They don't need to subvert DNS
records for you
to see cached websites. Unless they're doing something stupid, your web
requests are still made of the original IPs, just the results are
cached.
I have the same thing, here, on my LAN. A Squid proxy server, so that
if I have guests doing the "look at this" thing amongst themselves, or a
bunch of Windows PCs doing updates, everyone after the first query sees
the cached version.
You can try it out, and see. Find a public DNS server that you can
access on a different-than-usual port. Make a rule on your gateway that
connection attempts to your router IP and DNS port get redirected to the
external DNS server on the unusual port. It's probably possible to make
an outgoing redirection rule on the PC that your testing, itself.
As far as them optimising things, with satellite internet, there's a
prolonged propagation delay. So them doing local caching means that you
get to see cached data on this side of the satellite, rather than have
to wait for it to come through it.
Years ago I used an ISP that did that sort of thing, their service was
dreadful. Everything was late, worse than dial-up. Their crap
performance was the thing that pushed me into running my own DNS
servers. Their DNS servers were even worse than their everything else
that they did. Frequently, it could take half a minute for it to return
a result. When you consider that way too many pages are a construct of
data from here, there, and everywhere, not just the sites own service,
it could take an age to load a page.
Any service that mucks you about, and fobs you off, and leaves you
trying to resolve a problem for days on end, doesn't deserve your
custom. Especially if the problem is theirs.
As I said I don't know exactly what they are doing but I do know that
I'm not smart enough to work around it. I spent quite a bit of effort
Googling "Viasat Exede" and it seems there's a dearth of information
other than sales hype. Here's an excerpt from a interview I did find,
still not very informative:
"The teleports are associated regionally with customers, so there's no
dynamic routing being done by the satellite. "If we did routing in the
satellite, we'd be getting about 10 gigabits of throughput," Dankberg
said. "With bridging, we get more than 10 times that." Just for scale,
140 gigabits per second is 20 times the bandwidth capability of the
previously existing WildBlue satellite service. "The two largest
satellite operators have about a hundred satellites," Dankberg said,
"and between them they have the same bandwidth as this one
satellite."That sort of capacity, he says, alters the economics of
satellite broadband.
There are some things bandwidth can't overcome, and one of them is the
laws of physics. Satellite is still prone to latency, which means it's
not the best choice for applications that need a short
time-of-flight—like online gaming, for example (unless you're a big fan
of lag). "We tell people up front if they're looking for a gaming
connection, this isn't it," Dankberg conceded.
There's also a small, but noticeable delay on voice-over-IP phone calls
over Exede, but not any more than a typical wireless call. I placed a
call over a VoIP phone tethered to an Exede home unit, and the
conversation was better than cellular quality."
Source:
http://arstechnica.com/business/2012/01/how-viasats-exede-makes-satellite...
He makes it sound that it's essential to stick with their software, some
parts of which are apparently contained in the modem. As I said I am
quite happy with the service, it normally works well and there is
nothing better available to me. I also recently subscribed to their voip
service and find it superior to the cell phone [we discontinued the
land-line long ago] there is usually no detectable delay due to transit
time to the satellite. My only problem was the intermittent DNS. It has
not failed today that I am aware of. The kids are not happy due to it's
inability to handle on-line gaming with their brother in Chicago. That
is not a requirement in my book.
If anyone understands what they are doing and can explain it to me I am
interested.
Bob
--
http://www.qrz.com/db/W2BOD
box10 Fedora-19/64 bit Linux/XFCE