CCENT Fundamentals

IPv4 addressing:

IPv4 range.
1-126
128-191
192-223
224-239
240-255

Private Range:

10.0.0.0 10.255.255.255

172.16.0.0 172.31.255.255

192.168.0.0 192.168.255.255

Loopback :

127.0.0.1 127.255.255.255

127.0.0.0/8 loopback network

Note : 127.0.0.0 will not ping as it is the Network number.

Got this on Ubuntu:
jedi@jedi-OptiPlex-GX520:~$ ping 127.0.0.0
Do you want to ping broadcast? Then -b
jedi@jedi-OptiPlex-GX520:~$ ping 127.0.0.0 -b
WARNING: pinging broadcast address


TCP/UDP Port numbers:

0 - 1023 well-known
1024 -49151 registered
49152 - 65535 dynamic/private


Port Numbers

Both TCP and UDP:
7-ECHO
20-FTP Data
21 -FTP Control
22 -SSH
23 -TELNET
25 -SMTP
53 -DNS SERVER(TCP), DNS Clinet (UDP)
67- Bootstrap Protocol (BOOTP Server)
68 - Bootstrap Protocol (BOOTP Client)
69 -TFTP
79 - Finger
80 -HTTP
137-NetBIOS Name service
138-NetBIOS Datagram service
139-NetBIOS Session Service
162-SNMP Trap(both TCP UDP)
443 -HTTPS -both TCP UDP
546 both    TCP and UDP     DHCPv6 client   
547 both  TCP and UDP     DHCPv6 server

Only TCP:
110 -POP3
179 - BGP
1080 - Socks

Only UDP:
161- SNMP

Source: Wikipedia.org


VLSM:

IN the above diagram the /26 Networks are changed to /30
as this will save IP addresses. /26 which is 2^6 = 64, hence
64 - 2 = 62 Hosts on the Point to Point links, which is a waste.
Using /30 conserves IP's.Now the Networks on one side are /26
and on another side are /30.Classless Protocols like EIGRP,
OSPF,RIPv2,BGP etc are capable of recognizing and routing
the varied Subnets Masks.

Source: http://www.stevebrookes.id.au/mediawiki/index.php/Chapter_8_-_VLSM

Route Summarization / Route aggregation / Supernetting: 

Example1: 
 

 

Example 2 :

 

 

Source.