OT: internet/router question....

So, tell me, how does that one work then?

Reply to
The Natural Philosopher
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Depends. Google use all sorts of weird stuff. Maybe you enterd a postcode for that town once

Delete all browsing history and cookies and see what it then says.

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Reply to
The Natural Philosopher

I don't know how it works, just that I've been cuaght out by it in the past.

Apparently this is one way it's done:

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Reply to
Lee

I *think* the gist is that if the company is using this type of laod balancing and redirection, then the media server will think the user is geo-located at the DNS resolver location.

Something like that, anyway. Apparently it used to work for watching some US TV content before they got wise to it.

Reply to
Lee

Wrong end of the stick

Thats using broad IP ranges as assigned to e.g. RIPE to work out as a DNS serveice which continent you are in.

Not which semi in a suburban street

Reply to
The Natural Philosopher

No. It si wuite simply using a smart DNS server to assign different targets depending on the source address of the client.

Its just IP address geolocation on a per continent scale

Reply to
The Natural Philosopher

That's not how to find where someone is by using DNS ... it's how to use the fact that you already know where someone is (by another method) to send their traffic to a server near to them ...

Reply to
Andy Burns

yes.

And in fact if you have access to global BGP tables, the nearest server in 'internet' hop terms...

Reply to
The Natural Philosopher

All I know is being caught out by using a DNS resolver physically located in the US (can't remember why I was) and having a similar issue.

When I asked people for help in resolving the issue this is what I was told. And changing the DNS to a global one resolved the problem.

I was told that because the cache/balancing server that the company is using expects to see the closest DNS resolver being used, in some cases it (the media server) assumes this (the DNS resolver) as the physical location of the client requesting the media. I was told that where this is done, rather than IP geolocation, it is because it is quicker.

Again could be total BS for all I know.

Reply to
Lee

Traffic isn't sent to "a server near to them". It's sent towards a destination network. All that the source network knows, for a given destination address, is where to send the traffic to next. This holds true for subsequent networks until the packet arrives at the destination network, which will then send it to you. In IPv4 there's no geographical routing.

Reply to
Tim Streater

anycast routing, quite clever stuff.

Reply to
Andy Burns

yes, but it's because your IP was a USA address, that you got sent to a "local" DNS server, which gave you a DNS result of a (web?) server in the USA ...

Reply to
Andy Burns

I suggest you read up on BGP routing.

"BGP makes best-path decisions based on current reachability, *hop counts* and other path characteristics. In situations where multiple paths are available -- as within a major hosting facility -- BGP can be used to communicate an organization's own preferences in terms of what path traffic should follow in and out of its networks. BGP even has a mechanism for defining arbitrary tags, called communities, which can be used to control route advertisement behavior by mutual agreement among peers."

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Reply to
The Natural Philosopher

The packet has to have a destination server IP address before it ever leaves the source machine ... how it gets to the network that server is on is down to the routers in-between and could be seen as "going towards" at each hop.

Reply to
Andy Burns

Yes, but you seemed to imply it had a kindly "please look after this bear" destination label on it, rather than an explicit address ...

Reply to
Andy Burns

Yes, I used to have a bit to do with all of that, although it's been 10 years now. My recollection is that this tends to be done in a relatively static manner, so once set up, it's not modified (apart from reachability). You accept traffic from customers and then route it to a chosen exit point to the next network, with other exit points being given lower priority so they get used when a link goes down. Of course you keep tabs on traffic to make sure no link is getting overloaded and perhaps adjust the parameters from time to time.

My outfit usually had agreements with two global networks for them to take our commodity IP traffic, typically the likes of Telia, Sprint, Global Crossing ...

Reply to
Tim Streater

It'll have that before the packet is even assembled.

Reply to
Tim Streater

You have missed the point.

Lets say google who run their own primary name servers and who get a request from - well lets say BT internet name server...which proxies for all BT internet customers - or the stupid ones any way.

It looks at the source address of BT internet, determines it is UK and resolves the DNS request to a google server that is, because it also has BGP tables access, because Google runs its own Autnomous Network, the fewest number of hops from BT.

Then when the customer finished their DNS request - made to BTs proxy DNS server, they are handed the IP adress of et server closest to BTs network.

This all breaks down if tou manually configure your machines to use a US based DNS server.

Reply to
The Natural Philosopher

Indeed, but te point I was trying to make is that, as an AN, you see all the BGP statements. They are not filtered out until they get to te boundary roputers and if thoise atre YOIUR routers ypu can exxmine ebery single BGP update that comes your way.

For example you might geta a 'Sprint USA via 7 hops on this next hop' You (your big fat CISCO) would compare it with the table and see you already have that on a lower hop count via another internmediary and discount it.

BUT you could also realy that information to as server that is buidling an internet connectivity map. In fact you probably already have such. You can build these via traceroute type probing anyway.

Couple that to a DNS server that selects from multiple possible answers to 'where is youtube' and you have ways of managing regional vectoring.

Reply to
The Natural Philosopher

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