Define the terms LAN, WAN and MAN.
LAN - Local control, small, can be physically protected
WAN - Controlled by single organisation, larger distance, physically exposed
MAN - Covering a city or metropolitan area. Similar to WAN
Name four different types of topologies.
- Bus
- Ring
- Star
- Fully connected
List four potential problems with networking.
- Resource sharing
- Network complexity
- Attacker anonymity
- Many points of access/unknown access path
What is the simplest method of protecting a LAN?
Do not connect it to the internet. However, this isn’t always practical so a firewall should be used.
What are the functions of a firewall?
- Access control in both direction
- Virus Checking
- Statistical
- Masking the structure of the LAN to the outside world
A firewall should be constant, tamperproof, and simple.
What is packet filtering? How can the access be controlled?
Packet filtering is based on a series of riles blocking the flow of data to certain machine addresses and sources.
Access can be controlled by;
- Source address
- Destination
- Service requirement
- Local or outside IP Address
What is stateful inspection?
Stateful inspection means checking for characteristics of a small section of a packet against a database of accepted/banned actions.
Faster than scanning the whole packet.
HTTP, FTP, UDP, SMTP and SNMP are all ports/protocols. What do the stand for?
HTTP: hyper text transfer protocol FTP: file transfer protocol UDP: user datagram protocol SMTP: simple mail transport protocol SNMP: simple network management protocol
Firewalls are usually a special dedicated version of the following physical devices; router and gateway. What is a router and a gateway?
Router - a device that sends packets of information to the required destination. Internal messages can be sent directly whereas external messages are forwarded onwards.
Gateway - performs more substantial transforms on the packets (including modifications, mapping and encryption)
Both can be either hardware or software
