IPv4
Internet Protocol version 4 or IPv4 is the fourth version of the Internet Protocol (IP). IP is one of the core protocols for standards-based internetworking that is used on the Internet and other packet-switched networks.
IPv4 uses a 32-bit address space that provides 4,294,967,296 unique addresses. Addresses are expressed in dot decimal notation which consists of four octets of the address expressed individually in decimal numbers and separated by periods. The following are some examples of IPv4 address expressed in dot decimal notation, and their binary representations:
Dot decimal | binary |
---|---|
122.25.88.196 | 01111010.00011001.01011000.11000100 |
10.56.2.2 | 00001010.00111000.00000010.00000010 |
199.58.58.1 | 11000111.00111010.00111010.00000001 |
IPv4 uses the concept of a subnet mask to separate an address into the network portion and the host portion, giving IPv4 its hierarchical structure.
IPv4 resides on Layer 3 of the OSI model and is responsible for establishing unreliable end to end communication between hosts.
IPv4 was defined as a standard in 1981 and is still in widespread use today. IPv6 is the next version of the IP protocol which resolves many of the limitations that, over the years, the use of IPv4 has run into.
Links
https://datatracker.ietf.org/doc/html/rfc791
https://networklessons.com/cisco/ccna-200-301/internet-protocol
Links to this page:
- home
- ACL - Applying in a VRF environment
- ACL wildcard mask
- ARP Message Header and Payload
- ARP table
- ARP to Determine Next Hop IP Address
- ARP
- ASA - Understanding NAT behavior with DMZ Subnet
- ASA - using FQDN in an ACL
- ASA NAT translate_hits and untranslate_hits counters
- Access-List (ACL)
- Anycast Host Addressing
- BGP - AFI and SAFI
- BGP - Autonomous System (AS)
- BGP - Flowspec
- BGP - Labeled Unicast
- BGP - Leaking more specific routes
- BGP - Network Layer Reachability Information (NLRI)
- BGP - Next Hop Address Tracking vs Route Dampening
- BGP - multiprotocol BGP
- BGP - network command with subnet mask
- BGP - update-source command
- BGP - using public IPs with private ASes
- BGP Influencing incoming traffic
- BGP Influencing outgoing traffic
- BGP neighbor activate command
- Broadcast traffic
- CDP - best practices
- CPM - Cisco Performance Monitor
- CPM - Collect keyword
- Career study advice
- Carrier-Grade NAT
- Cisco Discovery Protocol (CDP)
- DHCP - Broadcast flag
- DHCP - Client ID
- DHCP - Commonly used options for IP phones
- DHCP - DHCPv6 and the default gateway
- DHCP - How a host is identified by a remote DHCP server
- DHCP - Message Types
- DHCP - Static binding use cases
- DHCP Request message sent as broadcast
- DHCP relay agent
- DHCP
- DHCPv6 relay agent
- DMVPN - NHRP purge request
- DMVPN - multicast commands
- DNS - Caching
- DNS - Recursive Resolver
- DNS - understanding zones
- DNS
- Debug Condition Command Restrictions in Cisco IOS
- EIGRP - Message TTL value of 2
- EIGRP - Understanding Advertised Distance (AD)
- EIGRP - shutdown command
- EIGRP Header
- EtherChannel - load balancing algorithms
- Ethernet VPN (EVPN)
- Ethernet frame types
- Ethernet header
- Ethernet over IP (EoIP)
- FHRP - HSRP Resign Message
- FHRP - which ports should you configure
- GRE - Understanding how keepalives work
- GRE Tunnel Addressing
- GRE
- Hot Standby Router Protocol (HSRP)
- IANA
- ICANN
- ICMP - Mitigating Vulnerabilities
- ICMP - Vulnerabilities
- IGMP - Snooping Querier Election
- IGMP - filtering using ACLs
- IGMP - ip igmp snooping querier command
- IGMP
- IGRP
- IOS - using ftp or tftp source-interface command
- IP - When is the TTL decremented in a router
- IP SLA - Route Flapping Problem
- IP routing table - 'L' and 'C' entries
- IP routing table - default route
- IPSec - Authentication Header (AH)
- IPSec - Encapsulating Security Payload (ESP)
- IPSec
- IPv4 - Internal Host Loopback Address Range
- IPv4 - ToS Byte definition
- IPv4 - classful addressing
- IPv4 - classless addressing
- IPv4 - header protocol field
- IPv4 - no subnet mask information in the IP header
- IPv4 - subnet mask
- IPv4 Link-local address range
- IPv4 Private IP address ranges
- IPv4 Subnetting invalid entry causing network address of zero
- IPv4 header length field
- IPv4 network and broadcast addresses
- IPv4 point to point addresses
- IPv6 - DHCPv6
- IPv6 - IPv4-mapped IPv6 address
- IPv6 - NDP Neighbor Discovery Process
- IPv6 - Network and Interface Identifiers
- IPv6 - SLAAC
- IPv6 - Site Local addresses
- IPv6 - Solicited Node Multicast Address
- IPv6 - loopback address
- IPv6 - prefix length
- IPv6 Neighbor Discovery Protocol Extensions
- IPv6 global unicast address
- IPv6 minimum and maximum prefix lengths
- IPv6 transition technologies
- IS-IS multitopology support
- IS-IS
- Interface - unknown protocol drops
- Intrusion prevention system (IPS)
- LFA - Topology Independent LFA
- LISP - what is it
- LISP
- MAC address of all zeros
- MAC address table static multicast entry
- MPLS - Connecting IPv6 sites over an IPv4 backbone
- MPLS - Disabling IPv4 address family in BGP for VPNv4
- MPLS - L3VPN BGP EIGRP redistribution
- MPLS - VPN label
- MPLS - Virtual Private Network (VPN)
- MPLS - label distribution using MP-BGP
- MPLS - label
- MPLS 6PE uses two labels in the data plane
- MPLS VRF names locally significant
- MPLS explicit NULL
- MPLS-TE - why are IGPs necessary
- MPLS
- MPP vs ACLs
- MTU - Adjusting MTU to accommodate additional headers
- MTU - Benefits of large L2 MTU
- MTU - Interface MTU vs IP MTU
- MTU - Path MTU Discovery (PMTUD)
- MTU - Understanding L2 MTU and Frame Handling in Network Switches
- Memory - TCAM Lookups
- Multicast - GLOP address space
- Multicast - Local Network Control Block
- Multicast - PIM Control Messages
- Multicast - routing over the Internet
- Multicast - troubleshooting multicast routing
- Multicast Anycast RP
- Multicast IPv4 address space
- Multicast MAC addresses
- Multicast Manual RP Configuration in Small PIM Networks
- Multicast mapping IP to MAC addresses
- NAT - Translation Table
- NAT - Twice NAT
- NAT - Virtual Interface (NVI)
- NAT - What is Policy NAT
- NAT - ip nat inside destination
- NAT - translate address not directly connected to edge device
- NAT Extendable on Cisco IOS
- NAT and IPv6
- NetFlow
- Network - Discontiguous
- Network - Example of communication, encapsulation, and decapsulation, between hosts
- Network - Monitoring multiple IPs of a single device with Observium
- Network - broadcast domain
- Network Address Translation (NAT)
- Networking - what is a socket
- Networks - Overlay Transport Virtualization (OTV)
- Networks - Underlay Network
- Next Generation Multicast Virtual Private Network (NG-MVPN)
- OSPF - A comparison with IS-IS
- OSPF - Database Example
- OSPF - Default route advertisement next hop IP
- OSPF - Link ID and ADV Router in the OSPF database
- OSPF - non-zero Forwarding Address example
- OSPF Forwarding Address
- OSPF IP Unnumbered
- OSPF IS-IS comparison
- OSPF area notation
- OSPF network command
- OSPF router ID in an IPv6 environment
- OSPF router ID
- OSPF
- OSPFv2 and OSPFv3 comparison
- OSPFv3 instance ID
- PBR - matching prefix lists
- PBR - set interface command
- PTP - Precision Time Protocol
- Ping - Specify ToS
- Ping - extended feature
- Ping - specifying size
- Point-to-Point Protocol (PPP)
- Prefix Lists - Operators
- Prefix Lists
- Protocol Data Unit (PDU)
- QoS - Assured Forwarding PHB values
- QoS - Classification by IP
- QoS - classification
- QoS - key and nonkey fields
- QoS - marking
- Real-time Transport Protocol
- Routing - Directed vs Local broadcast address
- Routing - Dynamic routing protocols
- Routing - How the routing table is populated
- Routing - address-family
- Routing - default gateway
- Routing - directed broadcast
- Routing - network vs redistribute connected commands
- Routing - redistribute command
- Routing Table
- Routing
- Security - Best Practices for Repurposing Network Devices
- Security - Next Generation Firewall
- Security - broadcast-multicast storm
- Security - spoofing
- Segment Routing
- Serial Interface default broadcast address
- Static ARP entry for own IP address
- Summarization
- Switching - CEF Adjacency Table
- Switching - switched virtual interface (SVI)
- Switchport - show vlan internal usage
- Syslog
- TCP - Determining the MSS
- TCP - factors affecting segment size
- TCP IP Model
- TCP MSS and window size
- Time to live
- Traceroute - Interpreting output
- UDP - Maximum Datagram Size
- VACL vs ACL
- VLAN Access Lists
- VPN - IKEv2 peer address of 0.0.0.0 0.0.0.0
- VPN - Interesting Traffic
- VPN - NAT Exemption
- VPN - default gateway of VPN client
- VRF - VPNv4 address
- VRRP - Virtual IP doesn't respond to pings
- VXLAN - Control Plane Options
- VXLAN - using an MP-BGP EVPN control plane
- VXLAN VTEP
- Wireless - configure a 1941W router with a single subnet on wired and wireless interfaces