Skip to content

DNS

netutils.dns

Functions for working with DNS.

fqdn_to_ip(hostname)

Provides the IP address of a resolvable name on the machine it is running from.

There are many reasons that a valid FQDN may not be resolvable, such as a network error from your machine to the DNS server, an upstream DNS issue, etc.

Parameters:

Name Type Description Default
hostname str

An FQDN that may or may not be resolvable.

 required

Returns:

Type Description
str

The IP Address of a valid FQDN.

Examples:

>>> from netutils.dns import fqdn_to_ip
>>> from netutils.ip import is_ip
>>> is_ip(fqdn_to_ip("google.com"))
True
>>>

Raises:

Type Description
gaierror

If FQDN is not resolvable, leverage is_fqdn_resolvable to check first.
Source code in netutils/dns.py 
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
def fqdn_to_ip(hostname: str) -> str:
    """Provides the IP address of a resolvable name on the machine it is running from.

       There are many reasons that a valid FQDN may not be resolvable, such as a network error
       from your machine to the DNS server, an upstream DNS issue, etc.

    Args:
        hostname: An FQDN that may or may not be resolvable.

    Returns:
        The IP Address of a valid FQDN.

    Examples:
        >>> from netutils.dns import fqdn_to_ip
        >>> from netutils.ip import is_ip
        >>> is_ip(fqdn_to_ip("google.com"))
        True
        >>>

    Raises:
        socket.gaierror: If FQDN is not resolvable, leverage is_fqdn_resolvable to check first.
    """
    # The data structure is complex, only require the first item, and drill down from there.
    return socket.getaddrinfo(hostname, 0)[0][4][0]

is_fqdn_resolvable(hostname)

Verifies whether a hostname is resolvable on the machine it is running from.

There are many reasons that a valid FQDN may not be resolvable, such as a network error from your machine to the DNS server, an upstream DNS issue, etc.

Parameters:

Name Type Description Default
hostname str

A FQDN that may or may not be resolvable.

 required

Returns:

Type Description
bool

The result as to whether or not the domain was valid.

Examples:

>>> from netutils.dns import is_fqdn_resolvable
>>> is_fqdn_resolvable("google.com")
True
>>> is_fqdn_resolvable("nevergonnagiveyouup.pizza")
False
>>>
Source code in netutils/dns.py 
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
def is_fqdn_resolvable(hostname: str) -> bool:
    """Verifies whether a hostname is resolvable on the machine it is running from.

       There are many reasons that a valid FQDN may not be resolvable, such as a network error
       from your machine to the DNS server, an upstream DNS issue, etc.

    Args:
        hostname: A FQDN that may or may not be resolvable.

    Returns:
        The result as to whether or not the domain was valid.

    Examples:
        >>> from netutils.dns import is_fqdn_resolvable
        >>> is_fqdn_resolvable("google.com")
        True
        >>> is_fqdn_resolvable("nevergonnagiveyouup.pizza")
        False
        >>>
    """
    try:
        socket.getaddrinfo(hostname, 0)
        return True
    except socket.error:
        return False