CCNA Notes

200-301 Exam Prep

Progress0/67

0% complete

Practice TestsNew
1Networking Devices2Interfaces And Cables3OSI Model and TCP/IP Suite4Intro to the CLI5Ethernet LAN Switching - Part 16Ethernet LAN Switching - Part 27IPv4 Addressing - Part 18IPv4 Addressing - Part 29Switch Interfaces10The IPv4 Header11Routing Fundamentals - Part 111Static Routing - Part 212Life of a Packet13Subnetting - Part 114Subnetting - Part 215Subnetting (VLSM) - Part 316VLANs - Part 117VLANs - Part 218VLANs - Part 319DTP / VTP20Spanning Tree Protocol - Part 121Spanning Tree Protocol - Part 222Rapid Spanning Tree Protocol23Etherchannel24Dynamic Routing25RIP / EIGRP26OSPF - Part 127OSPF - Part 228OSPF - Part 329First Hop Redundancy Protocol30TCP and UDP31IPv6 - Part 132IPv6 - Part 233IPv6 - Part 334Standard Access Control List35Extended Access Control List36CDP and LLDP37NTP - Network Time Protocol38DNS - Domain Name System39DHCP - Dynamic Host Configuration Protocol40SNMP - Simple Network Management Protocol41SYSLOG42SSH - Secure Shell43FTP and TFTP44NAT (Static) - Part 145NAT (Dynamic) - Part 246QoS (Voice VLAN) - Part 147QoS (Quality of Service) - Part 248Security Fundamentals49Port Security50DHCP Snooping51Dynamic ARP Inspection52LAN Architectures53WAN Architectures54Virtualization and Cloud - Part 154Virtualization (Containers) - Part 254Virtualization (VRF) - Part 355Wireless Fundamentals56Wireless Architectures57Wireless Security58Wireless Configuration59Introduction to Network Automation60JSON, XML, and YAML61REST APIs62Software Defined Networking63Ansible, Puppet, and Chef67CCNA Complete Cheatsheet
/NAT (Static) - Part 1
Topic 442 min read

NAT (Static) - Part 1

/
Tip: Select text to highlight or pin your reading position

44. NAT (STATIC): PART 1

PRIVATE IPv4 ADDRESSES (RFC 1918)

  • IPv4 doesn’t provide enough ADDRESSES for all DEVICES that need an IP ADDRESS in the modern world

  • The long-term solution is to switch to IPv6

  • There are THREE MAIN short-term solutions:

    • CIDR
    • PRIVATE IPv4 ADDRESS
    • NAT

  • RFC 1918 specifies the following IPv4 ADDRESS RANGES as PRIVATE:

    Code
    10.0.0.0 /8       (10.0.0.0 to 10.255.255.255)             CLASS A 
172.16.0.0 /12    (172.16.0.0 to 172.31.255.255)           CLASS B
192.168.0.0 /16   (192.168.0.0 to 192.168.255.255)         CLASS C

  • You are free to use these ADDRESSES in your NETWORKS. They don’t have to be GLOBALLY UNIQUE

imageClick to enlarge

INTRO TO NAT

  • NETWORK ADDRESS TRANSLATION (NAT) is used to modify the SOURCE and / or DESTINATION IP ADDRESSES of packets
  • There are various reasons to use NAT, but the MOST common reason is to ALLOW HOSTS with PRIVATE IP ADDRESSES to communicate with other HOSTS over the INTERNET
  • For the CCNA you have to understand SOURCE NAT and how to configure it on CISCO ROUTERS

imageClick to enlarge

STATIC NAT

  • STATIC NAT involves statically configuring ONE-TO-ONE MAPPINGS of PRIVATE IP ADDRESSES to PUBLIC ADDRESSES

imageClick to enlarge

imageClick to enlarge

imageClick to enlarge

PRIVATE IP CANNOT BE MAPPED TO THE SAME GLOBAL IP

THE SECOND MAPPING WILL BE REJECTED

imageClick to enlarge

STATIC NAT CONFIGURATIONS

imageClick to enlarge

imageClick to enlarge

Command clear ip nat translation

imageClick to enlarge

Command show ip nat statistics

imageClick to enlarge

COMMAND REVIEW

imageClick to enlarge

PreviousFTP and TFTP
NextNAT (Dynamic) - Part 2