For example, if I visit https://www.google.com, how do I get it to show on Wireshark? I've tried filtering by HTTP, but when I visit the website I don't see anything on Wireshark.
I'm really inexperienced at Wireshark and these kinds of things in general, and I would appreciate it if you could help!
You said you were filtering via HTTP which is port 80 TCP, but the address you are visiting is HTTPS which is port 443 TCP.
Related
I was having a doubt on how browser gets the data from website. I read these two links:
how can an application use port 80/HTTP without conflicting with browsers?
and
Port 80 blocked on my ISP so how my browser still works?
With this I understand that browser opens a local random source port and connect to port 80 of website. Now our system firewall have opened all outbound connection and blocked all incoming connection as default configuration. So how does it get back the response. Similarly how response comes back when our home routers and ISP have ports blocked.
So now, I am assuming that connection is somewhat different from response. And there must be some sort of header/information that is sent along which helps in recognizing it as response? And this helps in bypassing the ports?
My humble apologies in case I am messing up all terminologies and thanks for patience. I am beginner in this stuff. Any link towards guide will be very useful.
So how does it get back the response
Assuming you're talking about a firewall or NAT, these devices track outgoing connections, and allow replies to pass through. Connections are typically identified using Source IP + Destination IP + Source Port + Destination Port + Protocol (TCP/UDP). These connection identifiers are stored in a table in the NAT/Firewall.
I am interested in connecting to a web server I am running inside my home network on a Raspberry Pi. I have been reading up on how STUN servers work, and gather that they determine the port that the external facing router uses to redirect HTTP requests back to a device inside the local network.
I have an external website and I put a php file there to report back on the IP and port that requests come from. I can see that the requests come from the IP of my home router and each device uses a consistent port when a request is made.
If we assume my router has an external address of 123.123.123.123 and my Pi is allocated port 50500 for return requests I thought I would therefore be able to access the website on my Pi by using these combined as http://123.123.123.123:50500. However this does not work. Should this work?
(Note: port forwarding is not an option so please do not suggest that).
So I think the answer here is related to the fact that only UDP and TCP traffic are simple enough to get through the NAT using just the pi and port combination. I am trying to make a HTTP request over the same channel but this is more complex and therefore doesnt make it through.
That's pretty vague, and possibly not entirely correct. So I would love to hear from any experts in the field who can add more depth to this answer or correct me.
The ngrok is the easy and free one.
I setup webhook for social media in five minutes when develop IM robot .
There is a sample from Slack, but it apply to any social media or could solution which need webhook.
I'm wondering how L2TP works internally to provide transparent IP connectivity.
I understand that L2TP tunnels IP packets via UDP port 1721. However I don't see how this provides transparent access. For example let's say I have a VPN connection and my browser connects to google.com. It would normally make a TCP connection to google's IP address over port 80. However something has to intercept this request and route it through L2TP's mechanism.
In the Security Now podcast they did a 4 part series VPNs is great detail. The best part is that there are transcripts online so you don't have to listen to the whole thing if you know what to search for. here's a link to the main page http://www.grc.com/vpn/vpn.htm
This is a network programming question. I need to block all HTTP traffic using a layer 4 firewall (i.e it can look headers only upto TCP/UDP layers ). Is this possible?
As I was searching for a more accurate answer , I got to know that even if we cannot access HTTP header, we can access HTTP message field using layer 4 firewall.
No.
You can drop all TCP port 80 and port 443 traffic, but this might include traffic that isn't HTTP. (80 and 443 are open almost everywhere, so people (ab)use them often.) It will also miss HTTP traffic that happens on non-standard ports. (People do HTTP to port 8000 or 8080 or 8088 or 8888 all the time, in part because you don't need CAP_NET_BIND to be able to use high ports, in part because the numbers are easy to remember if port 80 is already used for something else.)
You can use the incoming port (ie 80) to detect HTTP traffic.
However you can't be 100% sure that's HTTP. But since it's the common port fort HTTP, I don't think many other applications use the port 80 for their communication.
If another port is used with HTTP protocol, you won't be able to block it this way, but it's a start.
Hey can any one tell me should i need open a port for outgoing request on http?
Well, your firewall might block outgoing connections on port 80 but this is quite rare.
So, the answer is "probably, but unlikely"