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description

sections.overview.title

sections.overview.content

privateRanges.title

10.0.0.0/8 - Class A private range
privateRanges.labels.fullRange 10.0.0.0 to 10.255.255.255
privateRanges.labels.totalAddresses 16,777,216 addresses
privateRanges.labels.commonUse Large enterprises, ISP internal networks
privateRanges.labels.examples
10.0.0.110.1.1.110.200.50.100
172.16.0.0/12 - Class B private range
privateRanges.labels.fullRange 172.16.0.0 to 172.31.255.255
privateRanges.labels.totalAddresses 1,048,576 addresses
privateRanges.labels.commonUse Medium businesses, cloud providers
privateRanges.labels.examples
172.16.0.1172.20.1.1172.31.255.254
192.168.0.0/16 - Class C private range
privateRanges.labels.fullRange 192.168.0.0 to 192.168.255.255
privateRanges.labels.totalAddresses 65,536 addresses
privateRanges.labels.commonUse Home networks, small offices
privateRanges.labels.examples
192.168.1.1192.168.0.100192.168.100.50

publicRanges.title

publicRanges.description

publicRanges.characteristics.title

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publicRanges.examples.title

publicRanges.examples.headers.publicIppublicRanges.examples.headers.ownerService
8.8.8.8Google Public DNS
1.1.1.1Cloudflare DNS
13.107.42.14Microsoft services
151.101.193.140Reddit

natImplications.title

Private Networks Accessing Internet
Private addresses must be translated to public addresses to reach the internet

natImplications.privateToPublic.process.title

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natImplications.privateToPublic.benefits.title

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Internet Accessing Private Networks
Direct access from internet to private IPs requires special configuration

natImplications.publicToPrivate.challenges.title

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natImplications.publicToPrivate.solutions.title

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identification.title

identification.headers.methodDescriptionidentification.headers.privateIndicatoridentification.headers.publicIndicator
IP Range CheckLook at first octets of IP address10.x.x.x, 172.16-31.x.x, 192.168.x.xAny other address not in reserved ranges
Reachability TestTry to reach from external networkCannot be reached from internetCan be reached from internet (if not firewalled)
Router ConfigurationCheck WAN vs LAN interface addressesLAN interfaces use private addressesWAN interface uses public address (unless CGNAT)

tools.title

whatismyipaddress.com
Shows your public IP as seen by internet
ipconfig / ifconfig
Shows local IP addresses on your device
Router admin page
Shows WAN (public) and LAN (private) IPs
traceroute
Shows path including public/private hops

commonScenarios.title

Home Network
commonScenarios.labels.setup Router gets public IP from ISP, creates private network inside
commonScenarios.labels.privateIps Devices use 192.168.1.x addresses
commonScenarios.labels.publicIp Router WAN interface gets ISP-assigned public IP
commonScenarios.labels.natBehavior All devices share the one public IP through NAT
Office Network
commonScenarios.labels.setup Firewall/router creates private network for employee devices
commonScenarios.labels.privateIps Computers use 10.x.x.x or 172.16.x.x addresses
commonScenarios.labels.publicIp Multiple public IPs for different services
commonScenarios.labels.natBehavior Outbound NAT for internet access, port forwarding for servers
Cloud Infrastructure
commonScenarios.labels.setup Virtual machines in private subnets with NAT gateway
commonScenarios.labels.privateIps VMs use 10.x.x.x addresses within VPC
commonScenarios.labels.publicIp Elastic/floating IPs assigned as needed
commonScenarios.labels.natBehavior NAT gateway for outbound, load balancers for inbound
CGNAT Environment
commonScenarios.labels.setup ISP uses CGNAT, customers get private IPs
commonScenarios.labels.privateIps Home router gets 100.64.x.x address (CGNAT range)
commonScenarios.labels.publicIp Shared among multiple customers
commonScenarios.labels.natBehavior Double NAT - home NAT + ISP CGNAT

troubleshooting.title

Can't Access Server from Internet

troubleshooting.labels.possibleCauses Server has private IP, No port forwarding, Firewall blocking

troubleshooting.labels.diagnosis Check if server IP is private, test port forwarding

troubleshooting.labels.solution Configure port forwarding or use public IP

Two Networks Can't Communicate

troubleshooting.labels.possibleCauses Both using same private range, No routing configured

troubleshooting.labels.diagnosis Check for IP address conflicts, routing tables

troubleshooting.labels.solution Use different private ranges or configure routing

VPN Not Working

troubleshooting.labels.possibleCauses Private IP conflicts, NAT traversal issues

troubleshooting.labels.diagnosis Check for address space overlap

troubleshooting.labels.solution Reconfigure IP ranges or use different VPN protocol

security.title

Private Network Security
  • Private IPs provide security through obscurity
  • Still need internal security measures
  • Lateral movement possible within private networks
  • Monitor internal network traffic
Public IP Security
  • Public IPs are constantly scanned and attacked
  • Require robust firewall and security measures
  • DDoS protection may be necessary
  • Regular security updates and monitoring essential

bestPractices.title

  • Use private IPs for internal networks
  • Reserve public IPs for internet-facing services only
  • Plan private IP ranges to avoid conflicts
  • Document your IP addressing scheme
  • Use DHCP for dynamic private IP assignment
  • Implement proper firewall rules for public IPs
  • Monitor public IP usage and costs

quickReference.title

quickReference.privateRanges.title
10.0.0.0/8 (10.0.0.0 - 10.255.255.255)
172.16.0.0/12 (172.16.0.0 - 172.31.255.255)
192.168.0.0/16 (192.168.0.0 - 192.168.255.255)
quickReference.identificationTips.title
If it starts with 10, 172.16-31, or 192.168 = private
If reachable from internet without NAT = public
Check your router - WAN IP is public, LAN IPs are private
Use online tools to see your public IP
Key Rule
If an IP starts with 10, 172.16-31, or 192.168, it's private. Everything else (except other reserved ranges) is public. Private IPs need NAT to reach the internet.