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 - hubs repeaters transceivers cabling

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 % 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 switchrouter to hub PC to switchPC to hub Cross-over (like interfaces)‏ switch to switchhub to hub switch to hubPC to PC Rollover Console into router

What happens when you use the wrong cable? ???????

Testing cables Using a cable tester us/products/MicroScanner+2/Overview.htm?categor ycode=CPTT

Fiber Multimode fiber – Supports up to 10Gbps (10 Gig)‏ Up to 550Meters Used commonly to interconnect wiring closets or buildings Single mode fiber – Supports up to 10Gbps (10 Gig)‏ Up to 60 Kilometers Used 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 Devices switch bridge

How do you find the MAC Address? Windows 1. Click Start 2. Run 3. cmd 4. ipconfig/all Mac 1. Open up a terminal 2. Type ifconfig

Two parts to the MAC Address XX – XX – XX – XX – XX - XX

Matching an OUI with a company

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)‏ Devices router layer 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

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 If you think you are having DNS issues you can try going to the IP address instead