Post on 23-Jan-2016
description
transcript
Sysops Network Training
by Brett Haffener
Introductions
- Name
- School
- What are you most interested in learning about?
Where do we start?
OSI Model
- Breaks up networking into smaller parts
OSI stands for (Open Systems Interconnection)
Taken from:en.wikipedia.org/wiki/OSI_Model
Layer 1 (Physical layer)
Media & Signalling
Devices include -
hubsrepeaterstransceiverscabling
Ethernet Cabling Standards
Categories of copper cabling:
Category 5: Limited to 100Mbps
Category 5e: Up to 1000Mbps (Gigabit)
Category 6: Up to 1000 Mbps
All three are limited to 100M (328ft) in length from end device to end device
Gig vs. 100Mbps
Backbone and server connections would be best at Gig
What category cabling should you use?
I recommend Cat6
Costs 20 - 40% more
Prepares you for the future
80-90% of new copper installs are now Cat6
Less interference between cables, so there are fewer errors causing fewer resent packets (slightly faster performance)
Types of cables
Straight through
Crossover
Rollover
Straight-through
Cross-over
Rollover
Where do I use each cable?
Straight through (unlike interfaces)router to switch router to hubPC to switch PC to hub
Cross-over (like interfaces)switch to switch hub to hubswitch to hub PC to PC
RolloverConsole into router
What happens when you use the wrong cable?
???????
Testing cables
Using a cable tester
http://www.flukenetworks.com/fnet/en-us/products/MicroScanner+2/Overview.htm?categorycode=CPTT
Fiber
Multimode fiber – Supports up to 10Gbps (10 Gig)Up to 550MetersUsed commonly to interconnect wiring closets or
buildings
Single mode fiber – Supports up to 10Gbps (10 Gig)Up to 60 KilometersUsed to connect geographically distant locations(not as common in schools)
Network Topology
Recommend extended star *** many schools daisy chain their switches ***
Layer 2 (Data-link layer)
Physical addressing
Switching
Devicesswitchbridge
How do you find the MAC Address?
Windows1. Click Start2. Run3. cmd4. ipconfig/all
Mac1. Open up a terminal2. Type ifconfig
Two parts to the MAC Address
XX – XX – XX – XX – XX - XX
Matching an OUI with a company
http://coffer.com/mac_find/
Tracking down a problem with the MAC Address
If you don't know where a machine is located you can use the MAC address to track it down (if you have managed switches)
Loops in the network
Loops are formed whenever there are redundant links in the network
Traffic continues around the loop generating excess traffic
Can cause broadcast storms (drastically reducing performance)
Spanning Tree
Spanning tree protocol prevents loops from occurring by blocking traffic on the extra interface
(Enabling spanning tree)
Spanning Tree (pros & cons)
Pros – If there is a loop in your network it won't take the entire network down
Cons – In the past Spanning Tree has slowed Mac logins down- If there is a loop in your network you may not know about it if you don't check your switches
*** Recommend using “Rapid Spanning Tree Protocol” if you are going to use this ***
Hubs vs. Switches
The major difference between hubs and switches is that hubs broadcast traffic out all interfaces whereas switches only sent unicast traffic out the destined interface
Speed & Duplex settings
Mismatched settings often times causes errors
Best to hard set connections between network devices when possible
Best to leave connections to workstations and servers in auto-negotiate (in general)
Layer 3
Logical addressing (IP addressing)
Devicesrouterlayer 3 switch
How routing works
Packet Tracer
Firewalls and port openings
The main place where you'll have to worry about ports being opened is in your firewall
Using netstat to see open ports
From the command line type:
Netstat -a
Wireless testing
http://www.netstumbler.com/
http://www.macstumbler.com/
Wireless security
Recommend WPA2
Public & Private wireless network
Troubleshooting tools
Ping
Traceroute
NSLOOKUP
Troubleshooting DNS
From a command prompt or terminal you can type nslookup <URL>
If you think you are having DNS issues you can try going to the IP address instead