Internet

1
Internet File Sharing - Part 2,
Without Wires
Dave Botherway, Melbourne PC User
Group
Dec 2007
2
A g e n d a

• Why Share ?
• I / P Addressing Concepts
• Simple Networking / File Sharing
• DHCP Dynamic Host Config Program
• Internet Gateway
• Router / Modem Sharing
• Wireless Connectivity Issues
• Simple Diagnostics
• Questions . . . .

3
W H Y ? ?

• WHY Share a) Maximise that old
  PC b) File Printer Sharing c)
  Multi-User Household
• Easier said than done . . . .
• Why the topic ? a) What to buy
  b) How to connect c) Security
  Issues
• It doesnt work ! Where Next ?

4
TCP / IP Addressing

• Telephone every Phone WW, a unique
  Number expanded via private PABX extensions
• Internet every device WW, a unique
  address expanded via private Gateway extensions
• Example - 240 . 12 . 23 . 81 ( IP v4
  ) max 255.255.255.255 -gt 4B addresses
  but not all usable -gt major shortage . .
• Two solutions a) private network
  gateways with NAT similar to a PABX b) IP
  v6, now available in Vista

5
Address Types IP MAC

• Typical (Class C) eg. 201. 82. 115.
  nnn 16m available, each with 256 extensions
  
• Not enough, so PABX / Gateway concepts used
• Reserved Gateway addresses via NAT,
  DHCP 10. nnn. nnn. nnn 19
  2. 168. nnn. nnn
• MAC (Media Access Control) address unique
  serial for each LAN device eg. Hex
  00-08-74-4C-7F-1D (48 bits)
• Identifies specific devices (but can be
  spoofed)

6
Simple I/P Addressing - Local Network
7
File Sharing across PCs

• Via File Explorer, setup Shared Directories
  and R-only or R/W Access on host PCs
• Use CrossOver cable, or LAN cables via Hub
• Manually enter IP addresses for each PC
• Test connectivity (ipconfig, ping) - demo
  later
• Via File Explorer, look at My Network
  Places (easier if using same Workgroup name)
• Copy files directly or Map as a local
  drive
• May need to establish Remote logon /
  Permission
• Similar process to share printers

8
Getting to the Outside World, via a
Gateway
9
External Addressing, via Gateway NAT
ting
10
But we use URLs - gt Domain Name Server
( DNS )
11
Thus for EACH pc, we need . . .

• Ethernet Connection RJ45 cable or
  Wireless
• TCP / IP Protocol s/w ( these days, a
  default )
• I P Address, either fixed or Gateway
  DHCP
• Gateway address where do I go next ?
• DNS location to translate URLs

12
Three PCs - One Modem
ISP provides external IP , DNS
to ISP
Single Port Modem
Router - with DHCP (Not just Hub)
RJ45
Wireless
Router / Gateway
Direct RJ 45 Cables
Router provides internal IP, NAT
13
D-Link 614 4P Wireless Router
14
Combo Modem Three PCs
to ISP Cable or ADSL
Multi-Port Wireless . Modem
Wireless
Modem-Router-GW
Direct RJ 45 Cables
Wi Fi Modem / Router - with DHCP
15
Wireless Router Defaults

• Admin address ( often 192.168.0.1 or
  10.0.0.1 )
• Default Logon and PSW ( admin / no psw )
• Default Channel ( usually 6, 1-13
  available )
• Default SSID ( brand name ) ON
• Wireless Security OFF
• No MAC limitations
• thus Easy to setup, to Share, to
  Hack
• Network Stumbler freebee Scanning
  Tool

16
Wireless Router Setup

• Connect via RJ45 cable, add Admin PSW
• Add Wireless PSW ( WEP, WPA-preferred
  )
• Change SSID (non identifiable ?)
• Then, on Wireless PC, Scan Listen
  to find unused channel (change Router
  Channel if needed) Select by SSID, should ask
  for Wireless PSW
• May need to Stop Firewall (or add new
  network as a trusted network )
• Test via cmd - ipconfig / all,
  ping router IP

17
IpConfig Output
Ping Output
18
Questions
Dave Botherway, Melbourne PC User
Group
Dec 2007