The iplib module

The iplib module contains functions, classes, and constants useful for managing IPv4 addresses and netmasks.

You can use this Python module (and the included scripts ipconv, nmconv, and cidrinfo) to convert amongst many different notations and to manage address/netmask pairs in CIDR notation.

iplib supports Python 3.10 through Python 3.16+ and includes complete type annotations.

Functions

Format check

These functions always return True or False (never raise exceptions) and can be called with any kind of arguments (integers, strings, and objects with a __str__() method which returns a suitable string):

• is_dot(ip): Return True if the IP address is in dotted decimal notation.
• is_hex(ip): Return True if the IP address is in hexadecimal notation.
• is_bin(ip): Return True if the IP address is in binary notation.
• is_oct(ip): Return True if the IP address is in octal notation.
• is_dec(ip): Return True if the IP address is in decimal notation.
• is_dot_nm(nm): Return True if the netmask is in dotted decimal notation.
• is_hex_nm(nm): Return True if the netmask is in hexadecimal notation.
• is_bin_nm(nm): Return True if the netmask is in binary notation.
• is_oct_nm(nm): Return True if the netmask is in octal notation.
• is_dec_nm(nm): Return True if the netmask is in decimal notation.
• is_bits_nm(nm): Return True if the netmask is in bits notation.
• is_wildcard_nm(nm): Return True if the netmask is in wildcard bits notation.

Format detection

Functions to detect IP/netmask notation; return IP_UNKNOWN/NM_UNKNOWN if the IP/netmask notation is not detected:

• detect(ip): Try to detect the notation of an IP address.
• detect_nm(nm): Try to detect the notation of a netmask.
• p_detect(ip) and p_detect_nm(nm): detect the notation of an IP address (or netmask) and return a nice string ('unknown' if it's not detected).
• is_notation(ip, notation) and is_notation_nm(nm, notation): return True if the given IP address (or netmask) is in the specified notation.

Conversions

Functions to convert IP/netmask; can raise a ValueError exception:

• convert(ip, notation=IP_DOT, inotation=IP_UNKNOWN) and convert_nm(nm, notation=IP_DOT, inotation=IP_UNKNOWN): Convert the given IP address (or netmask) to the given notation; the notation argument sets the notation of the output; the inotation argument forces the input to be considered as an address in the specified notation. When the IP address (or netmask) is an integer, the inotation argument is assumed to be IP_DEC (if not set otherwise).

Classes

IPv4Address

• IPv4Address(ip, notation=IP_UNKNOWN): This class represents an IPv4 Internet address.

An IPv4Address object can be used to sum or subtract two IP addresses or an integer offset:

>>> import iplib
>>> ip = iplib.IPv4Address('127.0.0.1')
>>> ip + 1000
<IPv4 address 127.0.3.233>

It's also possible to compare two IP addresses:

>>> iplib.IPv4Address('127.0.0.1') < iplib.IPv4Address('127.0.0.4')
True

For both IPv4Address and IPv4NetMask objects you can specify the notation:

>>> iplib.IPv4Address('24323', iplib.IP_OCT)
>>> iplib.IPv4Address('24323', 'oct')
>>> iplib.IPv4Address('24323', 'octal')

IPv4NetMask

• IPv4NetMask(nm, notation=IP_UNKNOWN): This class represents an IPv4 Internet netmask.

CIDR

• CIDR(ip, netmask=None): The representation of a Classless Inter-Domain Routing (CIDR) address.

From instances of this class, you can retrieve information about usable IP addresses, broadcast, and network address:

>>> cidr = iplib.CIDR('127.0.0.1/8')
>>> cidr.is_valid_ip('127.4.5.6')
True

Constants

The following constants are used to define IP/netmask notations:

• IP_DOT and NM_DOT: dotted decimal notation (e.g.: 192.168.0.42).
• IP_HEX and NM_HEX: hexadecimal notation (0xC0A8002A).
• IP_BIN and NM_BIN: binary notation (11000000101010000000000000101010).
• IP_OCT and NM_OCT: octal notation (0o30052000052).
• IP_DEC and NM_DEC: decimal notation (3232235562).
• NM_BITS: netmask in bits notation (24).
• NM_WILDCARD: netmask in wildcard bits notation (0.0.0.255).
• IP_UNKNOWN and NM_UNKNOWN: unknown notation.
• NOTATION_MAP: a dictionary mapping notations to valid string identifiers.
• VALID_NETMASKS: a dictionary mapping valid netmask bit lengths to decimal values.

License

This code is released under the BSD license.

Copyright

Copyright 2001-2026 Davide Alberani da@mimante.net