How External Traffic Reaches Devices Inside Your Network
Lets understand port forwarding feature by hosting internal web server.
Consider network like below:
You hosted web server in corporate network:
webserver (192.168.1.2) hosted on port 443------(Firewall or router)IP:185.4.34.21---------------Internet
In this video example, i am using these IP address for below components:
web server-192.168.1.2
Firewall or router public Ip-185.4.34.21
So our requirement is, if someone sitting in internet should be able to access web server.
If he access webserver with private IP address directly, he will not be able to access it as private IP address are
unroutable over internet.
So we need to find a way to access this web server.
How we can achieve it?
We can ask users to access this IP 185.4.34.21 on port 443, then that connection request reach router or firewall.
Now our target is to forward connection to the internal web server.
So we will do configuration rule in firewall or router like, if someone accessing this IP 185.4.34.21 on port 443,
it should forward connection to 192.168.1.2 on port 443.
So request would reach server and server respond back, this packet would reach router and router forwards connection
to the initiator.
Think of it like, if your company has employes we can set extension to each employee. So if someone dial company number
it will ask us if we know the extension. If we know the extension we can type extension and it will directly contact internal server.
Suppose, if you want to connect on different port, like this "185.4.34.21 on port 8010", its possible.
You will do configuration in firewall or router like if someone access this IP "185.4.34.21 on port 8010" it should
redirect to "192.168.1.2 on port 443"
We can also publish DNS record in the internet, for example if you want your users to access it using domain name.
Create DNS entry globally, like below:
www.firewallgeeks.com map it to "185.4.34.21"
So if any user access this domain "www.firewallgeeks.com", first user machine DNS request resolve to 185.4.34.21 so
user machine tries to contact this IP address and firewall or router can forward connection to the internal server.
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#networking #ccna #networksecurity #portforwarding #hostingwebserver
#webserverhostinginternally #internalwebserver #publicip #privateip
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