Difference between revisions of "Private LAN IP addresses"
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[[Category:Engineering]] | [[Category:Engineering]] | ||
+ | [[Category:Networking]] | ||
− | IP addresses reserved for private networks. These are routable only in a LAN; WAN gateways will not route the following IP addresses. The 192.168. | + | These IP addresses are reserved for '''private networks''' (sometimes called '''localnet'''). These are routable only in a LAN; WAN gateways will not route the following IP addresses. The 192.168.0.0/16 range is the most familiar. Often forgotten is the 172.16.0.0/12 range. |
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| 65026 | | 65026 | ||
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+ | |||
+ | == regex == | ||
+ | |||
+ | A regex to match an arbitrary IPv4 address can be quite tricky. The following get close for testing against private IP addresses. | ||
+ | <pre> | ||
+ | # localhost | ||
+ | allow ^127\.0\.0\.1$ | ||
+ | # localnets | ||
+ | # 192.168.0.0/16 | ||
+ | allow ^192\.168\.\d+\.\d+$ | ||
+ | # 172.16.0.0/12 | ||
+ | allow ^172\.(1[6-9]|2[0-9]|3[01])\.\d+\.\d+$ | ||
+ | # 10.0.0.0/8 | ||
+ | allow ^10\.\d+\.\d+\.\d+$ | ||
+ | # Link-local Zeroconf (/16 minus the first and last /24 ranges) | ||
+ | # WARNING: this should exclude the first and last /24 ranges, but it does not. | ||
+ | # This shouldn't matter since the first and last /24 ranges are reserved. | ||
+ | allow ^169\.254\.\d+\.\d+$ | ||
+ | </pre> |
Latest revision as of 10:47, 25 September 2013
These IP addresses are reserved for private networks (sometimes called localnet). These are routable only in a LAN; WAN gateways will not route the following IP addresses. The 192.168.0.0/16 range is the most familiar. Often forgotten is the 172.16.0.0/12 range.
IANA Reserved Private Network Ranges | Start of range | End of range | Total addresses |
---|---|---|---|
24-bit Block (/8, 1 x A) | 10.0.0.0 | 10.255.255.255 | 16777216 |
20-bit Block (/12, 16 x B) | 172.16.0.0 | 172.31.255.255 | 1048576 |
16-bit Block (/16, 256 x C) | 192.168.0.0 | 192.168.255.255 | 65536 |
Link-local Zeroconf (/16 minus the first and last /24 ranges) | 169.254.1.0 | 169.254.254.255 | 65026 |
regex
A regex to match an arbitrary IPv4 address can be quite tricky. The following get close for testing against private IP addresses.
# localhost allow ^127\.0\.0\.1$ # localnets # 192.168.0.0/16 allow ^192\.168\.\d+\.\d+$ # 172.16.0.0/12 allow ^172\.(1[6-9]|2[0-9]|3[01])\.\d+\.\d+$ # 10.0.0.0/8 allow ^10\.\d+\.\d+\.\d+$ # Link-local Zeroconf (/16 minus the first and last /24 ranges) # WARNING: this should exclude the first and last /24 ranges, but it does not. # This shouldn't matter since the first and last /24 ranges are reserved. allow ^169\.254\.\d+\.\d+$