A corporate firewall shields the internal network from the internet. When internal users want to access the internet, their requests must pass through an internal screening router which allows or blocks packets based on rules set by administrators. A bastion host located in the firewall perimeter network is the primary contact point for incoming internet connections for services like email and FTP access, providing an additional layer of security between the external network and internal corporate systems.

1. How corporate Firewalls works
● The firewall shields the
internal corporate
network from the
Internet.

2. The firewall want to acsess the Internet
When someone on the corporate network inside the
firewall wants to access the Internet, the request and
data must go through an internal screening router.

3. The screening certain packets
The screening router allows certain packets to be sent
or received, but blocks other packets.
System administrators set the rules for datermining
which packets to allow in and which ones to block.

4. A bastion host in the firewall
A bastion host in the firewall is the primary point of
contact for connections coming in from the Internet for
services such as receiving email and allowing access to
the corporation's FTP sites.

5. A bastion host
● The bastion host is
placed in a perimeter
network in the firewall,
so it is not on the
corporate network itself.

6. The exterior screening router
● An exterior screening
router screens packets
between the Internet and
the perimeternetwork.
● This router adds an extra
level of protection by
screening packets.