It may seem simple, but I'd like to know how a server gets your IP address. Is the web browser responsible for getting the IP address and reporting it in the header, or does the server trace the IP address somehow? Any insight you might have would be very much appreciated.
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How does a server get your IP? 1
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cyberspace
Technical User
on the internet "getting" ip addresses is done more by routers in the first instance.
So say you are downloading a file from via http (port 80)
When you type that address in, DNS converts the domain name to an IP address via means of a DNS lookup. Often this will be the address of the networks router (or indeed one of the routers) - the packet goes along its way and arrives at the router.
So within the router there may be firewall rules set up to deal with cetain requests on specific ports. So if you are contacting a web server for example, the destination IP address would be appended with the destination port of 80, eg. 162.85.33.177:80 - and would be forwarded via a firewall rule to the server designated to deal with these requests, ie, a web server....the router keeps track of these different 'conversations' by way of source port numbers which allow the router to differentiate between one data request and another...
Once past the router, the internal network may well be a private addressing scheme, again the port numbers come in to play here, as the server may respond to a request from, and return data to the ROUTER, which then 'translates' this destination back into the public address which originally requested the data, because it has the source port and therefore knows where it is going.
and hey presto, the router has your IP address and can send data back.
'When all else fails.......read the manual'
So say you are downloading a file from via http (port 80)
When you type that address in, DNS converts the domain name to an IP address via means of a DNS lookup. Often this will be the address of the networks router (or indeed one of the routers) - the packet goes along its way and arrives at the router.
So within the router there may be firewall rules set up to deal with cetain requests on specific ports. So if you are contacting a web server for example, the destination IP address would be appended with the destination port of 80, eg. 162.85.33.177:80 - and would be forwarded via a firewall rule to the server designated to deal with these requests, ie, a web server....the router keeps track of these different 'conversations' by way of source port numbers which allow the router to differentiate between one data request and another...
Once past the router, the internal network may well be a private addressing scheme, again the port numbers come in to play here, as the server may respond to a request from, and return data to the ROUTER, which then 'translates' this destination back into the public address which originally requested the data, because it has the source port and therefore knows where it is going.
and hey presto, the router has your IP address and can send data back.
'When all else fails.......read the manual'
cyberspace
Technical User
FYI I should have mentioned, the 'translation' process i mentioned is called NAT - Network Address Translation - and is used for saving public IP address space and as a security measure - entire organisations with thousands of hosts can have just one, or a few, public IP addresses.
By security, for example, I mean that a server does not have to sit directly on the internet, it can sit behind a router/firewall which will only allow access to specific areas of the server.
Hope this is useful...hope i havn't told you stuff you already know!
'When all else fails.......read the manual'
By security, for example, I mean that a server does not have to sit directly on the internet, it can sit behind a router/firewall which will only allow access to specific areas of the server.
Hope this is useful...hope i havn't told you stuff you already know!
'When all else fails.......read the manual'
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- #4
That was definitely helpful and I've given you a star for the invaluable information. However, I have more questions 
I recently stumbled upon Microsoft's Virtual Earth - a Google Maps clone - and was shocked to find that my IP address pinpointed my longitude and latitude. I've tried free services like GeoBytes before, but the results were anywhere from 1-5 miles off. Microsoft pinpointed my house almost exactly. To see for yourself, please go here:
It should give you your longitude and latitude, which you may paste into Google Maps, delimited by a comma. Alternatively, to see Virtual Earth's amazing Bird's Eye view, navigate to and type this in the address bar (my little workaround)..
javascript:map.PanToLatLong(<latitude>,<longitude>);
..and press enter or click Go.
Anyway, my question is, how is this possible? I suppose I understand that you can traceroute where the IP originates, but why is Microsoft deadly accurate as compared to the other services? It scares me :\
I recently stumbled upon Microsoft's Virtual Earth - a Google Maps clone - and was shocked to find that my IP address pinpointed my longitude and latitude. I've tried free services like GeoBytes before, but the results were anywhere from 1-5 miles off. Microsoft pinpointed my house almost exactly. To see for yourself, please go here:It should give you your longitude and latitude, which you may paste into Google Maps, delimited by a comma. Alternatively, to see Virtual Earth's amazing Bird's Eye view, navigate to and type this in the address bar (my little workaround)..
javascript:map.PanToLatLong(<latitude>,<longitude>);
..and press enter or click Go.
Anyway, my question is, how is this possible? I suppose I understand that you can traceroute where the IP originates, but why is Microsoft deadly accurate as compared to the other services? It scares me :\
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- #5
Sorry about the incorrect tag - I'm used to different messageboards :\
cyberspace
Technical User
Thanks for the star
I will check that out and get back to you!
However, USUALLY when you do visual traces by IP address it shows the location of your ISP, not the location of your house. When you connect to your ISP, you are allocated an IP address from their net block..this gives you access to the internet but should not (and i have never seen!) give your actual, precise, location
If this were the case then it would save the feds having to go through often lenghty procedures to retrieve the actual location of an IP address from an ISP!
But as I say, I will check it out as I have not used this service...but sounds interesting!
'When all else fails.......read the manual'
I will check that out and get back to you!
However, USUALLY when you do visual traces by IP address it shows the location of your ISP, not the location of your house. When you connect to your ISP, you are allocated an IP address from their net block..this gives you access to the internet but should not (and i have never seen!) give your actual, precise, location
If this were the case then it would save the feds having to go through often lenghty procedures to retrieve the actual location of an IP address from an ISP!
But as I say, I will check it out as I have not used this service...but sounds interesting!
'When all else fails.......read the manual'
It's only going to give the location of your ISP, or where ever/whoever your ip adress is registered to.
If you put your ip into and search it, you should find your isp's adress. I'd guess this is where its getting the information from
Stu
If you put your ip into and search it, you should find your isp's adress. I'd guess this is where its getting the information from
Stu
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Well I guess it's hit or miss, but I just tried again and it is dead on. I wonder if it has anything to do with my wireless router..? There's an option to install a WiFi type thing that attempts to locate your house, but I declined that and just used the IP address. I dunno, but however it does it is awesome.
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