Embedded Files
A good place to start
A good place to start
What is the internet
What is the internet
IP addresses & basic DNS
IP addresses & basic DNS
Quick look at various protocols
Quick look at various protocols
UDP
UDP
A more in-depth description of DNS
If you didn't like the one above, try this
Another more in-depth description of DNS of DNS
DNS nuaghtyness
SSH
SSH
Port forwarding
Port forwarding
Look up security issues with port forwarding...
Look up security issues with port forwarding...
6 networking tutorials from scratch
6 networking tutorials from scratch
"On the 25th of November 2019, RIPE NCC made the final /22 IPv4 allocation from the last remaining addresses in the available pool and has officially run out of IPv4 addresses. "
"On the 25th of November 2019, RIPE NCC made the final /22 IPv4 allocation from the last remaining addresses in the available pool and has officially run out of IPv4 addresses. "
INTRODUCTION TO NETWORKS
Networks connect devices, devices share information
To share information, they must speak the same language - this language is called a protocol.
Network types: SOHO network, enterprise network, LAN, WAN
Detail on copper & fibre cabling
Mentions that Ethernet protocol is specified by Institute of Electrical and Electronics Engineers (IEEE). Ethernet standard is: IEEE_802.3
Network protocols - several need to interact to send data over a network.
How they interact can be complicated and that is why we have Network models:.
This video is on the OSI model - owned by the International Standards Organisation (ISO)
IP Addressing.pdfVLSM - Variable Length Subnet Masks
unicast, broadcast & multicast.
IP addresses are assigned by the Internet Assigned Numbers Authority (IANA).
Static, dynamic IP Addresses and IPAPA addressing.
WORTH WHILE WATCHING
TCP/IP model - in competition to the OSI model.
Developed by the US Department of Defense. and become the most popular network model. Actively took into account existing protocols.
This model is in competition to the OSI model.
Covers http and therefore TCP and IP protocols.
Looking at specific protocols
Looking at specific protocols
Who manages the protocols?
Who manages the protocols?
The Internet Engineering Task Force (IETF) is an open standards organization, which develops and promotes voluntary Internet standards, in particular the standards that comprise the Internet protocol suite (TCP/IP).
The International Standards Organisation (OSI) is a multinational organization that tries to standardize network communication protocols at the international level. OSI (Open System Interconnection) is a model that ISO put together as a networking communication standard.
The Internet Consortium for Assigned Names and Numbers (ICANN) controls the DNS hierarchy and the allocation of IP addresses
OSI and TCP/IP Layers & associated protocols
OSI and TCP/IP Layers & associated protocols
HTTP & HTML
HTTP & HTML
TCP/IP
TCP/IP
A simple overview
A simple overview
TCP/IP
TCP/IP
A bit more in depth
A bit more in depth
UDP vs TCP
UDP vs TCP
The 5 layer network model is the TCP/IP model.
Goes into detail with UDP and TCP protocols.
HTTP, HTTPS & SSL
HTTP, HTTPS & SSL
FTP
FTP
POP3 vs IMAP
POP3 vs IMAP
The Future and Protocols
The Future and Protocols
From: APNIC - Internet protocols are changing
Background
Background
When the Internet started to become widely used in the 1990s, most traffic used just a few protocols: IPv4 routed packets, TCP turned those packets into connections, SSL (later TLS) encrypted those connections, DNS named hosts to connect to, and HTTP was often the application protocol using it all.
For many years, there were negligible changes to these core Internet protocols.
As a result, network operators, vendors, and policymakers that want to improve (and sometimes, control) the Internet have adopted a number of practices based upon the official protocol to tweak things, whether intended to debug issues, improve quality of service, or impose policy.
Now, significant changes to the core Internet protocols are underway. While they are intended to be compatible with the Internet at large (since they won’t get adoption otherwise), they might be disruptive to those who have taken liberties with undocumented aspects of protocols or made an assumption that things won’t change.
Why we need to change the Internet
Why we need to change the Internet
There are a number of factors driving these changes.
The limits of the core Internet protocols have become apparent, especially regarding performance. Because of structural problems in the application and transport protocols, the network was not being used as efficiently as it could be, leading to end-user perceived performance (in particular, latency).
This translates into a strong motivation to evolve or replace those protocols because there is a large body of experience showing the impact of even small performance gains.
The ability to evolve Internet protocols — at any layer — has become more difficult over time, largely thanks to the unintended uses by networks discussed above. For example, HTTP proxies that tried to compress responses made it more difficult to deploy new compression techniques; TCP optimization in middleboxes made it more difficult to deploy improvements to TCP.
Finally, we are in the midst of a shift towards more use of encryption on the Internet. Encryption is one of best tools we have to ensure that protocols can evolve and many protocols have been developed to insist on encryption.
You can read about these further by going to the APNIC site referenced above.
Determining the best network path
Determining the best network path
from CISCO
from CISCO
Determining the best path involves the evaluation of multiple paths to the same destination network and selecting the optimum or shortest path to reach that network. Whenever multiple paths to the same network exist, each path uses a different exit interface on the router to reach that network.
The best path is selected by a routing protocol based on the value or metric it uses to determine the distance to reach a network. A metric is the quantitative value used to measure the distance to a given network. The best path to a network is the path with the lowest metric.
Dynamic routing protocols typically use their own rules and metrics to build and update routing tables. The routing algorithm generates a value, or a metric, for each path through the network. Metrics can be based on either a single characteristic or several characteristics of a path. Some routing protocols can base route selection on multiple metrics, combining them into a single metric.
The following lists some dynamic protocols and the metrics they use:
Routing Information Protocol (RIP): Hop count
Open Shortest Path First (OSPF): Cisco routers use a cost based on cumulative bandwidth from source to destination
Enhanced Interior Gateway Routing Protocol (EIGRP): Bandwidth, delay, load, reliability
in case you thought networks were networks...
in case you thought networks were networks...
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