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is there a method to get default network interface on local using python3?

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If you are using Linux you can examining the route table directly on /proc/net/route. This file contains the routing parameters of your system, here is an example:

Iface Destination Gateway Flags RefCnt Use Metric Mask MTU Window IRTT
eth1 0009 C80A 00000000 0001 0 0 0 00 FFFFFF 0 0 0
eth2 0000790 A 00000000 0001 0 0 0 0080 FFFF 0 0 0
eth3 00007 A0A 00000000 0001 0 0 0 0080 FFFF 0 0 0
eth0 00000000 FE09C80A 0003 0 0 0 00000000 0 0 0

In this example all traffic to networks 10.200.9.0/24, 10.121.0.0/25 and 10.122.0.0/25 is broadcasted via eth1, eth2 and eth3 respectively, the rest of packages are sent using eth0 interface to the gateway 10.200.9.254. So the question is how to get this programatically using Python?

def get_default_iface_name_linux():
   route = "/proc/net/route"
with open(route) as f:
   for line in f.readlines():
   try:
   iface, dest, _, flags, _, _, _, _, _, _, _, = line.strip().split()
if dest != '00000000'
or not int(flags, 16) & 2:
   continue
return iface
except:
   continue

get_default_iface_name_linux() # will
return eth0 in our example

with pyroute2:

from pyroute2
import IPDB
ip = IPDB()
# interface index:
   print(ip.routes['default']['oif'])
# interface details:
   print(ip.interfaces[ip.routes['default']['oif']])
# release DB
ip.release()

The script below provides source IP address for default network interface (I.E. interface which routes traffic to 0.0.0.0/0):

from subprocess
import check_output
src_ip = check_output((
   "powershell -NoLogo -NoProfile -NonInteractive -ExecutionPolicy bypass -Command "
   "& {"
   "Get-NetRoute –DestinationPrefix '0.0.0.0/0' | Select-Object -First 1 | "
   "Get-NetIPAddress | Select-Object -ExpandProperty IPAddress"
   "}"
   ""
)).decode().strip()
print(src_ip)

The same for the default network interface itself:

check_output((
   "powershell -NoLogo -NoProfile -NonInteractive -ExecutionPolicy bypass -Command "
   "& {"
   "Get-NetRoute –DestinationPrefix '0.0.0.0/0' | Select-Object -First 1 | "
   "Get-NetIPConfiguration"
   "}"
   ""
)).decode().strip()

Suggestion : 2

Hi I want to get the default network anycodings_python interface using Python. After google, I got anycodings_python pynetinfo can do this. But pynetinfo seems anycodings_python not work on Python3. Is there another method anycodings_python to instead pynetinfo?,The same for the default network anycodings_routing interface itself:,Both provided answers don't address anycodings_routing Windows. In Windows I would suggest anycodings_routing using PowerShell.,The script below provides source IP anycodings_routing address for default network interface anycodings_routing (I.E. interface which routes traffic to anycodings_routing 0.0.0.0/0):

If you are using Linux you can examining anycodings_routing the route table directly on anycodings_routing /proc/net/route. This file contains the anycodings_routing routing parameters of your system, here anycodings_routing is an example:

Iface Destination Gateway Flags RefCnt Use Metric Mask MTU Window IRTT
eth1 0009 C80A 00000000 0001 0 0 0 00 FFFFFF 0 0 0
eth2 0000790 A 00000000 0001 0 0 0 0080 FFFF 0 0 0
eth3 00007 A0A 00000000 0001 0 0 0 0080 FFFF 0 0 0
eth0 00000000 FE09C80A 0003 0 0 0 00000000 0 0 0

In this example all traffic to networks anycodings_routing 10.200.9.0/24, 10.121.0.0/25 and anycodings_routing 10.122.0.0/25 is broadcasted via eth1, anycodings_routing eth2 and eth3 respectively, the rest of anycodings_routing packages are sent using eth0 interface anycodings_routing to the gateway 10.200.9.254. So the anycodings_routing question is how to get this anycodings_routing programatically using Python?

def get_default_iface_name_linux():
   route = "/proc/net/route"
with open(route) as f:
   for line in f.readlines():
   try:
   iface, dest, _, flags, _, _, _, _, _, _, _, = line.strip().split()
if dest != '00000000'
or not int(flags, 16) & 2:
   continue
return iface
except:
   continue

get_default_iface_name_linux() # will
return eth0 in our example

with pyroute2:

from pyroute2
import IPDB
ip = IPDB()
# interface index:
   print(ip.routes['default']['oif'])
# interface details:
   print(ip.interfaces[ip.routes['default']['oif']])
# release DB
ip.release()

The script below provides source IP anycodings_routing address for default network interface anycodings_routing (I.E. interface which routes traffic to anycodings_routing 0.0.0.0/0):

from subprocess
import check_output
src_ip = check_output((
   "powershell -NoLogo -NoProfile -NonInteractive -ExecutionPolicy bypass -Command "
   "& {"
   "Get-NetRoute –DestinationPrefix '0.0.0.0/0' | Select-Object -First 1 | "
   "Get-NetIPAddress | Select-Object -ExpandProperty IPAddress"
   "}"
   ""
)).decode().strip()
print(src_ip)

The same for the default network anycodings_routing interface itself:

check_output((
   "powershell -NoLogo -NoProfile -NonInteractive -ExecutionPolicy bypass -Command "
   "& {"
   "Get-NetRoute –DestinationPrefix '0.0.0.0/0' | Select-Object -First 1 | "
   "Get-NetIPConfiguration"
   "}"
   ""
)).decode().strip()

Suggestion : 3

PACKET_HOST (the default) - Packet addressed to the local host.,A tuple (interface, ) is used for the AF_CAN address family, where interface is a string representing a network interface name like 'can0'. The network interface name '' can be used to receive packets from all network interfaces of this family.,AF_PACKET is a low-level interface directly to network devices. The packets are represented by the tuple (ifname, proto[, pkttype[, hatype[, addr]]]) where:,Return a network interface name corresponding to an interface index number. OSError if no interface with the given index exists.

sock = socket.socket(
   socket.AF_INET,
   socket.SOCK_STREAM | socket.SOCK_NONBLOCK)
import socket

addr = ("", 8080) # all interfaces, port 8080
if socket.has_dualstack_ipv6():
   s = socket.create_server(addr, family = socket.AF_INET6, dualstack_ipv6 = True)
else:
   s = socket.create_server(addr)
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(<AddressFamily.AF_INET6: 10>, <AddressFamily.SOCK_STREAM: 1>,
      6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
      (<AddressFamily.AF_INET: 2>, <AddressFamily.SOCK_STREAM: 1>,
            6, '', ('93.184.216.34', 80))]
import socket, array

def recv_fds(sock, msglen, maxfds):
   fds = array.array("i") # Array of ints
msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
for cmsg_level, cmsg_type, cmsg_data in ancdata:
   if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
   # Append data, ignoring any truncated integers at the end.
fds.frombytes(cmsg_data[: len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
return msg, list(fds)
>>>
import socket
   >>>
   s1, s2 = socket.socketpair() >>>
   b1 = bytearray(b '----') >>>
   b2 = bytearray(b '0123456789') >>>
   b3 = bytearray(b '--------------') >>>
   s1.send(b 'Mary had a little lamb')
22
   >>>
   s2.recvmsg_into([b1, memoryview(b2)[2: 9], b3])
   (22, [], 0, None) >>>
   [b1, b2, b3]
   [bytearray(b 'Mary'), bytearray(b '01 had a 9'), bytearray(b 'little lamb---')]
import socket, array

def send_fds(sock, msg, fds):
   return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])

Suggestion : 4

Last Updated : 24 Nov, 2020,Technical Scripter 2020

Installation:

pip install netifaces

Suggestion : 5

Bind your service incoming traffic only to a dedicated interface. If you need to bind more than one interface using the built-in socket module, create multiple sockets (instead of binding to one socket to all interfaces).,In this example, two sockets are insecure because they are bound to all interfaces; one through the 0.0.0.0 notation and another one through an empty string ''.,Inconsistent method resolution order,Mutation of descriptor in __get__ or __set__ method.

ID: py / bind - socket - all - network - interfaces
Kind: problem
Severity: error
Precision: high
Tags:
   -security -
   external / cwe / cwe - 200
Query suites:
   -python - code - scanning.qls -
   python - security - extended.qls -
   python - security - and - quality.qls
import socket

# binds to all interfaces, insecure
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0', 31137))

# binds to all interfaces, insecure
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('', 4040))

# binds only to a dedicated interface, secure
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('84.68.10.12', 8080))

Suggestion : 6

Pure-Python package to get the MAC address of network interfaces and hosts on the local network.,It provides a platform-independent interface to get the MAC addresses of:,The Python standard library has a robust set of networking functionality, such as urllib, ipaddress, ftplib, telnetlib, ssl, and more. Imagine my surprise, then, when I discovered there was not a way to get a seemingly simple piece of information: a MAC address. This package was born out of a need to get the MAC address of hosts on the network without needing admin permissions, and a cross-platform way get the addresses of local interfaces.,Significantly improved default interface detection. Default interfaces are now properly detected on Linux and most other POSIX platforms with ip or route commands available, or the netifaces Python module.

Stable release from PyPI

pip install getmac

Latest development version

pip install https: //github.com/ghostofgoes/getmac/archive/master.tar.gz

Python examples

from getmac
import get_mac_address
eth_mac = get_mac_address(interface = "eth0")
win_mac = get_mac_address(interface = "Ethernet 3")
ip_mac = get_mac_address(ip = "192.168.0.1")
ip6_mac = get_mac_address(ip6 = "::1")
host_mac = get_mac_address(hostname = "localhost")
updated_mac = get_mac_address(ip = "10.0.0.1", network_request = True)

# Changing the port used
for updating ARP table(UDP packet)
from getmac
import getmac
getmac.PORT = 44444 # Default: 55555
print(getmac.get_mac_address(ip = "192.168.0.1", network_request = True))

# Enabling debugging
from getmac
import getmac
getmac.DEBUG = 2 # DEBUG level 2
print(getmac.get_mac_address(interface = "Ethernet 3"))

Add -v /proc/1/net/arp:/host/arp -e ARP_PATH=/host/arp to access arp table of host inside container in bridge network mode.

docker build - f packaging / Dockerfile - t getmac.
docker run - it getmac: latest--help
docker run - it getmac: latest--version
docker run - it getmac: latest - n localhost
docker run--rm - it - v / proc / 1 / net / arp: /host/arp - e ARP_PATH = /host/arp
getmac: latest - n 192.168 .0 .1

Suggestion : 7

This article mainly addresses Python-specific debugging configurations, including the necessary steps for specific app types and remote debugging.,See Debugging specific app types for details on all of these configurations.,Note: To change debugging configuration, your code must be stored in a folder.,Provides the name for the debug configuration that appears in the VS Code dropdown list.

In the script code, add the following and save the file:

import debugpy

# 5678 is the
default attach port in the VS Code debug configurations.Unless a host and port are specified, host defaults to 127.0 .0 .1
debugpy.listen(5678)
print("Waiting for debugger attach")
debugpy.wait_for_client()
debugpy.breakpoint()
print('break on this line')

Enable port forwarding by opening the sshd_config config file (found under /etc/ssh/ on Linux and under %programfiles(x86)%/openssh/etc on Windows) and adding or modifying the following setting:

AllowTcpForwarding yes

In your VS Code workspace, create a configuration for remote debugging in your launch.json file, setting the port to match the port used in the ssh command and the host to localhost. You use localhost here because you've set up the SSH tunnel.

{
   "name": "Python: Attach",
   "type": "python",
   "request": "attach",
   "port": 5678,
   "host": "localhost",
   "pathMappings": [{
      "localRoot": "${workspaceFolder}", // Maps C:\Users\user1\project1
      "remoteRoot": "." // To current working directory ~/project1
   }]
}

In the source code, add the following lines, replacing address with the remote computer's IP address and port number (IP address 1.2.3.4 is shown here for illustration only).

import debugpy

# Allow other computers to attach to debugpy at this IP address and port.
debugpy.listen(('1.2.3.4', 5678))

# Pause the program until a remote debugger is attached
debugpy.wait_for_client()

Launch the remote process through debugpy, for example:

python3 - m debugpy--listen 1.2 .3 .4: 5678--wait -
   for -client - m myproject

Local computer: Only if you modified the source code on the remote computer as outlined above, then in the source code, add a commented-out copy of the same code added on the remote computer. Adding these lines makes sure that the source code on both computers matches line by line.

#import debugpy

# Allow other computers to attach to debugpy at this IP address and port.
#debugpy.listen(('1.2.3.4', 5678))

# Pause the program until a remote debugger is attached
#debugpy.wait_for_client()


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