Do they automatically send all the sites open on the browser through the vpn, or does the traffic not get sent through the vpn until the pages are refreshed?
Depends on if anything loads after you connect to the VPN. If you already have the webpage completely rendered, then there will be no requests from the website being sent to the VPN
When you initiate a VPN you default route will be though the VPN gateway, if it's intended to provide internet access. However, if its just to reach specific subnets on the peer end of the VPN tunnel then the VPN tunnel will be used for that specific subnets.
Although, HTTP uses TCP connection it doesn't keep the connection open after sending all the requested data and upon successfully received by the browser.
Assuming you have the first scenario and HTTP connection behavior it will start sending traffic though the VPN if you refresh or click any hyper link in the page(as this will create a new TCP connection to request that data.
Related
I want to be able to send POST requests from devices outside of my network to my PC.
I am not able to port forward from the router settings page and all of my previous attempts to use UPnP have not worked.
Is there another way that I can send requests to my PC?
I am using my device as an Access Point and I need to display a deafault web page once somebody is connected.
Right now I have to connect to a specific IP (socket parameters: IP 192.168.0.1 , PORT 80) to show the page.
The page doesn't need to open automatically, it just has to show up no matter what URL gets inserted in the browser.
I've read the RFC7710 but I'm not able to implement "low level" solutions such as modify the option 160 of the DHCP.
The best thing for me would be to work at the HTTP level.
Any ideas?
HTTP works on the top of the TCP/IP infrastructure, it requires an established TCP connection first. As long as there is no TCP connection from the client to the HTTP server, the server has no way to tell, force, or trick a client to connect to its IP address and TCP port. No connection, no HTTP.
when a browser sends a request to a web server, the web server has to send a response.
from what i have understood from reading so far, the server than dispatches the packets of response data with dest-port/dest-ip parts being the client browser's.
1) If the above is right, than doesn't it mean that the browser has to always be listening to a port for incoming traffic from the server?
2) And if the client is listening for incoming connections on a port, isn't that a security concern?
3) If 2 is right, than how are most corporate firewalls for employees be configured? (seeing as they probably need to browse the net) - a quick overview, details unnecessary.
doesn't it mean that the browser has to always be listening to a port for incoming traffic from the server?
No. Layman's explanation: a browser initiates a TCP connection to the web server. This connection is recognized by source ip and port, dest ip and port and protocol by all intermediate level 3 machines (e.g. routers, firewalls).
In a TCP connection, one party listens (the web server) while the other party connects (the browser). Traffic can flow over this connection in both directions, until either party (or intermediate machine) closes the connection.
Corporate firewalls allow outbound connections over port 80 (and 443), so their employees can browse the web over HTTP(S). The data the server returns is sent over the connection initiated by the client.
Of course if an outside attacker knows of a connection, they can send packets with a spoofed IP, so they can send data pretending to be the server. Those packets will be dropped if anything is wrong, like the sequence number, so they won't end up in the user's browser.
Suppose I have a VPS with private networking setup such that the only ports that are open are the port for SSHing into the server and the port that connects the server to other servers on the private network. Can this same server still send requests through the internet and receive back responses? If so, through what 'channel' are the requests/responses being sent/received?
It depends on what the outbound firewall settings are on the server. If the firewall allows all outbound connections then you can connect out to any server on any protocol.
However, depending on the hosting provider, they may limit the ports which you can use for outbound connections. Most likely (but not guaranteed) you'll be able to use HTTP (80) and HTTPS (443). It is quite possible that SSH (22) would be open as well. Those three should cover most, if not all, of the needs to would have.
I'm trying to learn the basics of ARP/TCP/HTTP (in sort of a scatter-shot way).
As an example, what happens when I go to google.com and do a search?
My understanding so far:
For my machine to communicate with others (the gateway in this case),
it may need to do an ARP Broadcast (if it doesn't already have the
MAC address in the ARP cache)
It then needs to resolve google.com's IP address. It does this by
contacting the DNS server. (I'm not completely sure how it knows
where the DNS server is? Or is it the gateway that knows?)
This involves communication through the TCP protocol since HTTP is
built on it (TCP handshake: SYN, SYN/ACK, ACK, then requests for
content, then RST, RST/ACK, ACK)
To actually load a webpage, the browser gets the index.html, parses
it, then sends more requests based on what it needs? (images,etc)
And finally, to do the actual google search, I don't understand how
the browser knows to communicate "I typed something in the search box
and hit Enter".
Does this seem about right? / Did I get anything wrong or leave out anything crucial?
Firstly try to understand that your home router is two devices: a switch and a router.
Focus on these facts:
The switch connects all the devices in your LAN together(including the router).
The router merely connects your switch(LAN) with the ISP(WAN).
Your LAN is essentially an Ethernet network which works with MAC addresses.
For my machine to communicate with others (the gateway in this case),
it may need to do an ARP Broadcast (if it doesn't already have the MAC
address in the ARP cache)
Correct.
When you want to send a file from your dekstop to your laptop, you do not want to go through the router. You want to go through the switch, as that is faster(lower layer). However you only know the IP of the laptop in your network. For that reason you need to get its MAC address. That's where ARP kicks in.
In this case you would broadcast the ARP request in the LAN until someone responds to you. This could be the router or any other device connected to the switch.
It then needs to resolve google.com's IP address. It does this by
contacting the DNS server. (I'm not completely sure how it knows where
the DNS server is? Or is it the gateway that knows?)
If you use DHCP, then that has already provided you with the IP of the DNS server. If not, then it means that you manually provided the IP of the DNS. So the IP of the DNS server is stored locally on your computer.
Making a DNS request is just about putting its IP in the packet with the request and forwarding the packet to the network.
Sidenote: DHCP also provides the IP address of the router.
This involves communication through the TCP protocol since HTTP is
built on it (TCP handshake: SYN, SYN/ACK, ACK, then requests for
content, then RST, RST/ACK, ACK)
Yes. To clarify things: When your computer sends the request
FRAME[IP[TCP[GET www.google.com]]]
The frame is being sent to your LAN's switch which forwards it to the MAC of the router. Your router will open the frame to check the destination IP and route it accordingly(in this case to the WAN). Finally when the frame arrives at the server, the server will open the TCP segment and read the payload, which is the HTTP message. The ACK/SYN etc. messages are being processed just by your computer and the server and not any router or switch.
To actually load a webpage, the browser gets the index.html, parses
it, then sends more requests based on what it needs? (images,etc)
Yes. An HTML file is essentially a tree structure which can have embedded resources like images, javafiles, CSS etc. For each such resource a new request has to be sent.
Once your browser gets all these recourses, it will render the webpage.
And finally, to do the actual google search, I don't understand how
the browser knows to communicate "I typed something in the search box
and hit Enter".
When you type a single character, it is being sent to the server. The server then responds with its suggestions. Easy as that.
References(good reads):
http://www.tcpipguide.com/free/t_TheNeedForAddressResolution.htm
http://www.howtogeek.com/99001/htg-explains-routers-and-switches/
http://www.eventhelix.com/realtimemantra/networking/ip_routing.htm#.UsrYAvim3yO
http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol