Pablumfication

While setting up some iptables rules the other day to allow connections from a clients IP range to are servers in London. I needed to translate an IP range expressed as a CIDR to real from and to values. I remembered being taught how to do so in college but that was a long time ago now so was looking for an online tool, I couldn’t find any I liked so I checked for a Linux tool. I found one called sipcalc which is really good. Not only can it do what I needed with translating the CIDR notation it can do a few other calculations / conversions as well.

Simple install process under Ubuntu just the usual

sudo apt-get install sipcalc

Once install its ready to go. To convert an IP range expressed in CIDR format you simply do

sipcalc 165.19.104.1/23

-[ipv4 : 165.19.104.1/23] - 0

[CIDR]
Host address            - 165.19.104.1
Host address (decimal)  - 2769512449
Host address (hex)      - A5136801
Network address         - 165.19.104.0
Network mask            - 255.255.254.0
Network mask (bits)     - 23
Network mask (hex)      - FFFFFE00
Broadcast address       - 165.19.105.255
Cisco wildcard          - 0.0.1.255
Addresses in network    - 512
Network range           - 165.19.104.0 - 165.19.105.255
Usable range            - 165.19.104.1 - 165.19.105.254

This is what I needed to do and it worked just fine giving me the network range and more.

Another useful one is to pass in an IP address and subnet mask this once again is a simple way of getting details about the IP range

sipcalc 10.0.1.84 255.255.0.0

-[ipv4 : 10.0.1.84 255.255.255.0] - 0

[CIDR]
Host address            - 10.0.1.84
Host address (decimal)  - 167772500
Host address (hex)      - A000154
Network address         - 10.0.1.0
Network mask            - 255.255.255.0
Network mask (bits)     - 24
Network mask (hex)      - FFFFFF00
Broadcast address       - 10.0.1.255
Cisco wildcard          - 0.0.0.255
Addresses in network    - 256
Network range           - 10.0.1.0 - 10.0.1.255
Usable range            - 10.0.1.1 - 10.0.1.254

The final example which is probably the most useful to people is to pass in an interface as the parameter

sipcalc -i eth0

-[int-ipv4 : eth0] - 0

[CIDR]
Host address            - 109.123.80.196
Host address (decimal)  - 1836798148
Host address (hex)      - 6D7B50C4
Network address         - 109.123.80.0
Network mask            - 255.255.255.0
Network mask (bits)     - 24
Network mask (hex)      - FFFFFF00
Broadcast address       - 109.123.80.255
Cisco wildcard          - 0.0.0.255
Addresses in network    - 256
Network range           - 109.123.80.0 - 109.123.80.255
Usable range            - 109.123.80.1 - 109.123.80.254