LINK LOCAL ADDRESS

 LINK LOCAL ADDRESS 

always starts w/ "fe80" followed by 3 clusters of 4 zeros

Ex. = fe80:0000:0000:0000 [last half is auto generated]

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GLOBAL UNICAST ADDRESS aka IPv6 is automatically generated by your PC + ROUTER

Use COMMAND SCREEN: ">ipconfig" to see your IPv6 address

SUBNET MASK does not really apply to IPv6

IPv6 uses a prefix length stuck at "/64" in place of SUBNET MASK

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PORT NUMBERS

*Web browser is a web client. They use WEB SERVERS  (like "apache" or "i.i.s.")

DNS = Domain name system: like a speed-dialer that zips you to a site's WEB SERVER

After IP address & DNS - a PORT NUMBER gets you to the right application

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PORT# example: 0-65535 

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*when browsing internet there are 2 port #s* 

The "SOURCE" port + "DESTINATION" PORT numbers (like a train)

Webpage DATA < PORT 1 (source) < PORT 2 # (destination) < outgoing IP < intercepting IP

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Like the post office, web server just flips the destination/source - then sends back

(So different webpage tabs don't open the wrong info from multiple web-servers)

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*FYI you can see all web-server data going back & forth between ports via RESOURCE MONITOR*

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DIFFERENT TYPES OF "PORTS"

1) 0-1023 "Well Known Ports"

2) 1024-49151 "registered ports"

3) 49152-65535 "dynamic ephemeral ports"

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**PORTS on the COMPTIA EXAM** 

21-FTP

22-SSH

23-TELNET

25-SMTP

53-DNS

80-HTTP

110-POP3

161/162-SNMP

143-IMAP

443-HTTPS

4489-RDP

137-139-NETBIOS/NETBT

445-SMB.CIFS

427-SLP

548-AFP

67/68-DHCP

389-LDAP

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TCP/IP, UDP, ICMP:

TCP/IP = TRANSMISSION CONTROL PROTOCOL / INTERNET PROTOCOL

Connection based protocol. 2 servers talking to each other *digital handshake

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UDP = connectionless protocol. Automated service at ice cream shop

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ICMP = single packets of info. small Working class commands of the internet

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PDU = protocol data unit 

What part are we interested in? The frame = IP packet

tiny parts of data frame chain: "TCP segment / UDP datagram"

*3 different PDUs*

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UNDERSTANDING DNS

DNS is like a contact list / speed dialer for the IP addresses of specific websites

DNS replaced "Host file"

ROOT SERVERS: only control one qualified domain

they're 1ST LEVEL DOMAINS like .com, edu, org, etc.

2nd level is DNS - ex: google

ROOT SERVERS top of the family tree 

.com  .edu  .gov

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then DNS 2nd level domains

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then bottom level = my computer LOL

(When browser says "waiting for server" its going through the above family tree. Caching will save websites you've previously visited)

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DNS server /FQDNS are limited to 256 characters (So be careful) 

But 98% of the time DNS works just fine

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WORKING with DNS

Your DHCP server usually provides the DNS

Open COMMAND SCREEN to see your DNS server - ipconfig /all

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HOW TO STATICALLY CONFIGURE DNS SERVER:

CONTROL PANEL, NETWORK SHARING, CHANGE ADAPTOR SETTINGS, right click PROPERTIES, IPv properties, keep IP address automatic but manually enter 2 DNS server addresses

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Alternate DNS is just a bunch of 8s?? or 8.8.4.4

"nslookup" tool: will let you see if a DNS server is working. If DNS times out, you'll know it's down.

Open COMMAND SCREEN - "nslookup"