Answer for HTTPS/SNI support: Use the HostHeaderSSLAdapter in the requests_toolbelt module:

The above solution works fine with virtualhosts for non-encrypted HTTP connections. For HTTPS you also need to pass SNI (Server Name Identification) in the TLS header which as some servers will present a different SSL certificate depending on what is passed in via SNI. Also, the python ssl libraries by default don't look at the Host: header to match the server connection at connection time.

The above provides a straight-forward for adding a transport adapter to requests that handles this for you.

Example

import requests

from requests_toolbelt.adapters import host_header_ssl

# Create a new requests session
s = requests.Session()

# Mount the adapter for https URLs
s.mount('https://', host_header_ssl.HostHeaderSSLAdapter())

# Send your request
s.get("https://198.51.100.50", headers={"Host": "example.org"})

I think the best way to send https requests to a specific IP is to add a customized resolver to bind domain name to that IP you want to hit. In this way, both SNI and host header are correctly set, and certificate verification can always succeed as web browser.

Otherwise, you will see various issue like InsecureRequestWarning, SSLCertVerificationError, and SNI is always missing in Client Hello, even if you try different combination of headers and verify arguments.

requests.get('https://1.2.3.4/foo.php', headers= {"host": "example.com", verify=True)

In addition, I tried

requests_toolbelt

pip install requests[security]

forcediphttpsadapter

all solutions mentioned here using requests with TLS doesn't give SNI support

None of them set SNI when hitting https://IP directly.

# mock /etc/hosts
# lock it in multithreading or use multiprocessing if an endpoint is bound to multiple IPs frequently
etc_hosts = {}


# decorate python built-in resolver
def custom_resolver(builtin_resolver):
    def wrapper(*args, **kwargs):
        try:
            return etc_hosts[args[:2]]
        except KeyError:
            # fall back to builtin_resolver for endpoints not in etc_hosts
            return builtin_resolver(*args, **kwargs)

    return wrapper


# monkey patching
socket.getaddrinfo = custom_resolver(socket.getaddrinfo)


def _bind_ip(domain_name, port, ip):
    '''
    resolve (domain_name,port) to a given ip
    '''
    key = (domain_name, port)
    # (family, type, proto, canonname, sockaddr)
    value = (socket.AddressFamily.AF_INET, socket.SocketKind.SOCK_STREAM, 6, '', (ip, port))
    etc_hosts[key] = [value]


_bind_ip('example.com', 443, '1.2.3.4')
# this sends requests to 1.2.3.4
response = requests.get('https://www.example.com/foo.php', verify=True)

You'd have to tell requests to fake the Host header, and replace the hostname in the URL with the IP address:

requests.get('http://123.45.67.89/foo.php', headers={'Host': 'www.example.com'})

The URL 'patching' can be done with the urlparse library:

parsed = urlparse.urlparse(url)
hostname = parsed.hostname
parsed = parsed._replace(netloc=ipaddress)
ip_url = parsed.geturl()

response = requests.get(ip_url, headers={'Host': hostname})

Demo against Stack Overflow:

>>> import urlparse
>>> import socket
>>> url = 'http://stackoverflow.com/help/privileges'
>>> parsed = urlparse.urlparse(url)
>>> hostname = parsed.hostname
>>> hostname
'stackoverflow.com'
>>> ipaddress = socket.gethostbyname(hostname)
>>> ipaddress
'198.252.206.16'
>>> parsed = parsed._replace(netloc=ipaddress)
>>> ip_url = parsed.geturl()
>>> ip_url
'http://198.252.206.16/help/privileges'
>>> response = requests.get(ip_url, headers={'Host': hostname})
>>> response
<Response [200]>

In this case I looked up the ip address dynamically.