Infrastructure

TCP/IP Suite Architectural Layers
Layer	Protocols	Responsibility
Application	HTTP, HTTP Secure, FTP, SMTP, Telnet, DNS, RDP, SNMP, & POP	Give applications access to specific services in order to exchange data.
Transport	TCP & UDP	Provides the application layer with session and datagram communications services (Dulaney & Easttom, 2014).
Internet	IP, ARP, & ICMP	Routes information, gives IP addresses, and packages data.
Network Access	All of the above	Communicates with network adapters to remove and place packets throughout the network.

 Encapsulation can be compared to an onion as it has many different layers that are involved.  This process permits the host-to-host protocol to send across the network which through each layer it obtains an additional header of information as it is sent.  This process is extremely important to understand as it can be helpful when troubleshooting data loss and possible vulnerabilities within the network. 

There are encapsulation vulnerabilities that we all need to be aware of as they can be easily exploited.  These are called inter-protocol exploitation considering it is a type of vulnerability that takes advantage of two communication protocols.  The most commonly found protocols that are exploited are SMTP, POP, and many more.

When designing a secure network, two technologies of which I would utilize are Virtual Local Area Networks (VLAN) and Demilitarized Zones (DMZ).  A VLAN is a segmentation that allows you to conceal portions of the network from other sections.  The reason of which VLAN's are used in a secure network is it can enclose network traffic to a specific area within the network.  A DMZ is used to send data into three different directions in order to control the traffic.  This gives you the ability to hide servers from people you may not trust on the network.  The key to DMZ is isolation and that in itself is why it is used in the topology of a secure network.

There are three different types of firewalls, one of which is a packet filter firewall, the next being a proxy firewall, and then there is a stateful packet inspection firewall.  All of which secure the network by checking packets but in different ways.  Each firewall is different by how it processes the incoming and outgoing packet, even how it allows or denies them also.

 For example, a packet filter firewall examines incoming packets on specific ports to ensure they contain the correct information for the address it is sending to.  Whereas, a proxy firewall will only examine data, such as packets to decide if it will be forwarded or blocked internally.  Lastly, the stateful packet inspection firewall uses memory and records to track and ensure the packet is traveling the correct channels.

The number one vulnerability within routers is their software as they can be extremely buggy as the ISP sets them up improperly.  The best way to reduce this threat is once a router is installed immediately configure it appropriately for your network usage.  The second router vulnerability that intrigues me is the weak default password that most people do not change.  The obvious way to reduce this issue is to change the password upon setup.

One of the vulnerabilities that affect switches are called finger service, which if it is enabled it allows an attacker to collect credentials and then close the connection.  In order to reduce this risk make sure this service is not enabled at all times.  Switches also have a small service that is enabled by default on older models.  This service allows the user to diagnose and troubleshoot possible issues, but hackers can take advantage of them by launching denial-of-service attacks.  This is another easy vulnerability to avoid if you make sure this service is disabled when not in use.

References

Cisco Router/Switch Common Security Vulnerabilities and Router/Switch Hardening. (n.d.). Retrieved 11 25, 2016, from OmniSecu: http://www.omnisecu.com/ccna-security/cisco-router-switch-security-vulnerabilities-and-hardening.php

Dulaney, E., & Easttom, C. (2014). CompTIA Security+ Study Guide, Sixth Edition. Indianapolis: John Wiley & Sons,.

Horowitz, M. (n.d.). Router Bugs Flaws Hacks and Vulnerabilities. Retrieved 11 25, 2016, from Router Security: http://routersecurity.org/bugs.php

Inter-protocol Exploitation. (2008, 08 15). Retrieved 11 25, 2016, from Hakipedia: http://hakipedia.com/index.php/Inter-protocol_Exploitation