network engineering

User10.1.1.10MAC @:A11188Firewall 110.1.1.1MAC @:A11122.1.1.1 MAC @:A22111Firewall 2 (NO NAT)22.1.1.2MAC@ AFF11233.1.1.1MAC @:AC3111NAT 10.1.1.10 – 22.1.1.10Firewall 3Firewall 4(NO NAT)NAT 10.3.1.20 – 33.1.1.2010.2.1.1MAC @:ABBD1110.2.1.2MAC@ 88DFE1210.3.1.1MAC @: 56354Server10.3.1.20MAC@: 9876AA33.1.1.2MAC @:ACC112

The user at 10.1.1.10 is sending an HTTP packet to the server on network E.

Please indicate for each step, the characteristics of the packet (Source MAC address, destination MAC address, IP source address, IP destination address, source port, destination port) and where does it goes next, and why. If that decision involved routing table decisions, please document the appropriate routing table entry used.

Packet at User going to: __________________________ :

Source MAC:

Destination MAC:

Source IP:

Destination IP:

Source Port:

Destination Port:

Reason why the packet goes there next:

Routing table entry (if applicable):

Packet at __________________ going to: ________________________ :

Source MAC:

Destination MAC:

Source IP:

Destination IP:

Source Port:

Destination Port:

Reason why the packet goes there next:

Routing table entry (if applicable):

Packet at __________________ going to: ________________________ :

Source MAC:

Destination MAC:

Source IP:

Destination IP:

Source Port:

Destination Port:

Reason why the packet goes there next:

Routing table entry (if applicable):

Packet at __________________ going to: ________________________ :

Source MAC:

Destination MAC:

Source IP:

Destination IP:

Source Port:

Destination Port:

Reason why the packet goes there next:

Routing table entry (if applicable):

Packet at __________________ going to: Server

Source MAC:

Destination MAC:

Source IP:

Destination IP:

Source Port:

Destination Port:

Reason why the packet goes there next:

Routing table entry (if applicable):

Problem 4 – Network and Security Design – 6 points

COMPANY OVERVIEW

A small corporation with 50 workstations and 1 server has a LAN and runs all applications from the server. This includes web, Email (SMTP-based), a proprietary application (JP-APP) which uses TCP port 1234 and DNS.

The network is currently not connected to the internet and is implemented using a “bogus” IP addressing scheme of 128.0.0.0/16

Your job is to design a new infrastructure or modified the network infrastructure to allow connectivity to the Internet via a dedicated T1.

Your ISP has assigned you a class C public address of 204.11.22.0 for your usage and made their DNS (IP address 22.33.44.55) available for your use.

You have been allowed to purchase and implement:

Up to two firewall with 2 or 3 interfaces that are capable (if required) to perform NAT.

One router not capable of any filtering nor NAT

One additional hub or switch

One new server with all necessary software.

All necessary manpower required for implementation and modification (if necessary) of the current environment - I.E.: you are working overtime with no extra pay ;)

You need to provide:

Ability for users to access web servers on Internet

Mail exchange with all except competitor

Allow the CEO’s home computer on the Internet (IP address 12.2.3.4) to access JP-APP

Must block all traffic to your competitor that has a public IP address of 145.33.0.0 / 16

Setup of a public web page accessible by all, except competitors. (New web site that is static and developed by outside consultants) It must accessible as http://www.myweb.com

Present a design including diagram, IP address assignment, filtering rules for the firewall, NAT/PAT rules and also present important DNS entries.

Present also any other recommendations you would propose to improve the environment’s security infrastructure if you didn’t have to work within the requirements above.