London Grid for Learning schools conference 28 th april 2014

1. London Grid for Learning schoolsconference 28thapril2014

2. LGfL Schools Conference 2014 Supporting the New Curriculum Techspeak made Simple Brian Durrant Chief Executive LGfL

3. Purpose: to de-mystify some network related tech speak • Audience: teachers – non-tech • Digital • Network address • Internet Protocol • DHCP • DNS • Gateway • Subnet • Ports • DMZ • Domain • Firewall

5. A simple network

6. 4 – way handshake • Are you there station 42? • Yes – I’m ready • Here it is • Ok – got it! • A Protocol – an agreed method of communication

7. Maths Lesson 0000 0001 0000 0010 0000 0011 0000 0100 128 64 32 16 8 4 2 1 1 0 0 0 0 0 0 0 = 1 0 0 0 0 0 0 1 = 1 1 1 1 1 1 1 1 = 0 0 0 0 0 0 0 0 = 0 1 0 0 0 0 0 1 = A

8. Internet IPv4 11111111.11111111.11111111.11111111 = 256 x 256 x 256 x 256 = 4,294,967,296 ‘Station’ address (IP Address) : 82.2.159.118 (4 ‘octets’) Network No 82.2.159 Station No 118 (for example) Router – is this for this network? (‘subnet’) – or another ?

10. Internet IPv4 11111111.11111111.11111111.11111111 = 256 x 256 x 256 x 256 = 4,294,967,296 ‘Station’ address (IP Address) : 82.2.159.118 (4 ‘octets’) Network No 82.2.159 Station No 118 (for example) Router – this network (‘subnet’) – or another ? 4.3bn - enough? Private addresses - 10.X.X.X 192.168.X.X (internal only) Public (‘real world’) addresses - 82.2.159.118

11. DHCP - Dynamic Host Configuration Protocol Most computers don’t have an IP address they ‘own’ An IP address is allocated ‘on loan’ – a dynamic address Some devices need a fixed IP address (e.g. a printer) Some need a ‘public’ address (e.g. a web server) Start > cmd > ipconfig

12. Subnet mask (e.g. 255.255.255.0) To guide the traffic… 11111111.11111111.11111111.00000000 [ ------ Network address ------ ] [host address] [ ------- Subnet identity ---------] [device identity] = 254 devices “look at the first 24 bits to decide: – here, or elsewhere?” 11111111.11111111.11111000.00000000 [ ------- Subnet identity ----][device identity] = 2046 devices Subnet mask : 255.255.248.000 e.g. 10.163.2.0/21

13. Gateway ( e.g. 192.168.0.1 ) The link to the outside world – usually the router (i.e the link to the next network) So – all computers/devices on a network have an address - some static, some dynamic - some private (local), some public (world-wide) 82.2.159.118

14. DNS Domain Name System

15. Where’s my DNS service ? (e.g. 194.168.4.100 - via DHCP service) Hey DNS – where’s “LGFL.net” ? DNS : “It’s at 82.2.159.118” OK Router – “Connect me to 82.2.159.118”

16. OK Router – “Connect me to 82.2.159.118” A secure filtered connection to the Internet….. using Webscreen 2.0

17. What are ‘Port Numbers’ ? 82.2.159.118 : 80

18. DMZ – ‘Demilitarised Zone’ A subnet which exposes external-facing services to an untrusted network, usually the Internet. Provides a layer of security to the main internal network.

19. A Domain Name The part of a network address which identifies it as belonging to a particular domain. Used for websites - www.conference.lgfl.net And email addresses – brian@lgfl.net

20. Firewall • TCP/IP – is fast, powerful and therefore dangerous • Connected to the Internet, your school’s network is connected to every other computer connected to the Internet ! • A firewall helps prevent hackers or malicious software from gaining access to your network/computer. • Every LGfL connection comes with a dedicated managed firewall

22. A Tension - A Balance Absolute _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Absolute Security Freedom

23. Questions

24. London Grid for Learning schoolsconference 28thapril2014