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filter in scapy function sniff() says libpcap is not available

I was playing around with the Scapy sniff function and I wanted to add a filter into the parameters. So I added this filter:
pkt = sniff(count=1, filter='arp')
and the output i recieve is:
WARNING: Cannot set filter: libpcap is not available. Cannot compile filter !
I still get a packet that was sniffed, but for some reason the filter is not working.
I am running Mac OS Big Sur. I have libpcap installed using Homebrew and I have tcpdump installed using Homebrew.
I also saw online that you could manually initialize pcap on Scapy using
conf.use_pcap = True
However when I type this in I get:
WARNING: No libpcap provider available ! pcap won't be used
I'm sure it is just a small fix but I can't seem to figure out what I am doing wrong. If anyone can help that would be amazing!

Older versions of Python 3 assume that, on macOS, all shared libraries are in files located in one of a number of directories.
That is not the case in Big Sur; instead, a cache file is generated for system shared libraries, and at least some of the libraries from which the cache file is generated are not shipped with the OS.
This is one of the issues in CPython issue 41100, "Support macOS 11 and Apple Silicon Macs"; the fix is to look in the shared library cache as well as in the file system.
That issue says
Thank you to everyone who contributed to this major undertaking! A particular thank you to Lawrence for doing much of the initial work and paving the way. Now that 3.8 also supports Big Sur and Apple Silicon Macs as of the imminent 3.8.10 release, it's time to close this issue. If new concerns arise, pleasa open or use other issues.
So a sufficiently recent version of Python should fix this issue.

tldr:
$ brew install libpcap
$ ln -s /usr/local/opt/libpcap/lib/libpcap.a /usr/local/lib/libpcap.a
$ ln -s /usr/local/opt/libpcap/lib/libpcap.dylib /usr/local/lib/libpcap.dylib
Explanation (applicable for Python 3.9.1, Scapy 2.4.5 # Big Sur and libpcap installed by brew):
When you debug the Scapy sniff function, after a while you get to scapy.libs.winpcapy, line 36:
_lib_name = find_library("pcap")
find_library is located in ctypes.util, for POSIX it starts on line 72. On line 73 you can see that the library is expected as one of these filenames ['libpcap.dylib', 'pcap.dylib', 'pcap.framework/pcap'], being fed to dyld_find.
dyld_find is located in ctypes.macholib.dyld on line 121. If you iter through the chain on line 125 yourself, you find out that dyld_find is trying to succeed with one of these paths:
/usr/local/lib/
/Users/<user>/lib/
/usr/local/lib/
/lib/
/usr/lib/
In my case none of them contained the libpcap lib, which is installed in different location by brew.
The library sits in /usr/local/opt/libpcap/lib/.
And here you go, you just need to get the file libpcap.dylib (nothing wrong with libpcap.a too) into one of those paths searched by dyld_find. The two soft links above are one of a few more possible solutions.

ipython up and down arrow strange behaviour

In my installation of ipython I have this strange problem where I cannot reliably move through command history with up and down arrows... a lot of the time it just doesn't work (nothing happens on the key press). Also sometimes writing normal characters at the end of the command just doesn't work.
My system: Mac OSX Lion
I have readline installed...
thank you for the help!
david

Make sure you installed readline before ipython.
sudo pip uninstall ipython
sudo pip install readline ipython
(I know this question is a few months old, but for future reference)

I had to install readline with easy_install readline and that fixed it.
Using pip install readline did not work for me, and ipython gave a warning:
******************************************************************************
libedit detected - readline will not be well behaved, including but not limited to:
* crashes on tab completion
* incorrect history navigation
* corrupting long-lines
* failure to wrap or indent lines properly
It is highly recommended that you install readline, which is easy_installable:
easy_install readline
Note that `pip install readline` generally DOES NOT WORK, because
it installs to site-packages, which come *after* lib-dynload in sys.path,
where readline is located. It must be `easy_install readline`, or to a custom
location on your PYTHONPATH (even --user comes after lib-dyload).
******************************************************************************

Following trouble in iPython and up-&-down arrows to access history, and browsing this post, a simple solution (turn off "Scroll lock") turned out to work for me.

This is an intentional feature of IPython. If you type "abc" and then hit the up arrow, it's going to scroll only through lines that start with "abc". If you hit lift/right while you're scrolling, it triggers the same behavior. The entire contents of the current line are interpreted as your search prefix, any only lines starting with all that will show up on further up/down keypresses.
You can change this behavior in your PYTHONSTARTUP file. I have the following lines:
import readline
# Prevent ctrl-p/ctrl-n/Up/Down from doing prefix searching
readline.parse_and_bind('"\\C-p": previous-history')
readline.parse_and_bind('"\\C-n": next-history')
readline.parse_and_bind('"\\e[A": previous-history')
readline.parse_and_bind('"\\e[B": next-history')
If you're curious, here are the bindings in IPython's source code that we're overriding.
Unrelated, but I also like to to override readline's default ctrl-w:
# Ctrl-W behavior more like Vim
readline.parse_and_bind('"\\C-w": backward-kill-word')

mysql for python 2. 7 says Python v2.7 not found

I have downloaded mysql-connector-python-1.0.7-py2.7.msi from MySQL site
and try to install but it gives error that
Python v2.7 not found. We only support Microsoft Windows Installer(MSI) from python.org.
I am using Official Python v 2.7.3 on windows XP SP3 with MySQL esssential5.1.66
Need Help ???

I met the similar problem under Windows 7 when installing mysql-connector-python-1.0.7-py2.7.msi and mysql-connector-python-1.0.7-py3.2.msi.
After changing from "Install only for yourself" to "Install for all users" when installing Python for windows, the "python 3.2 not found" problem disappear and mysql-connector-python-1.0.7-py3.2.msi was successfully installed.
I guess the problem is that mysql connector installer only looks for HKEY_LOCAL_MACHINE entries, and the things it looks for might be under HKEY_CURRENT_USER etc. So the solution that change the reg table directly also works.

The Solution I get for this problem is
I have found Adding Python to Registry, the script as follows applicable for python v 2.0 and above:
Register a Python Interpreter
#
# script to register Python 2.0 or later for use with win32all
# and other extensions that require Python registry settings
#
# written by Joakim Low for Secret Labs AB / PythonWare
#
# source:
# http://www.pythonware.com/products/works/articles/regpy20.htm
import sys
from _winreg import *
# tweak as necessary
version = sys.version[:3]
installpath = sys.prefix
regpath = "SOFTWARE\\Python\\Pythoncore\\%s\\" % (version)
installkey = "InstallPath"
pythonkey = "PythonPath"
pythonpath = "%s;%s\\Lib\\;%s\\DLLs\\" % (
installpath, installpath, installpath)
def RegisterPy():
try:
reg = OpenKey(HKEY_LOCAL_MACHINE, regpath)
except EnvironmentError:
try:
reg = CreateKey(HKEY_LOCAL_MACHINE, regpath)
SetValue(reg, installkey, REG_SZ, installpath)
SetValue(reg, pythonkey, REG_SZ, pythonpath)
CloseKey(reg)
except:
print "*** Unable to register!"
return
print "--- Python", version, "is now registered!"
return
if (QueryValue(reg, installkey) == installpath and
QueryValue(reg, pythonkey) == pythonpath):
CloseKey(reg)
print "=== Python", version, "is already registered!"
return
CloseKey(reg)
print "*** Unable to register!"
print "*** You probably have another Python installation!"
if __name__ == "__main__":
RegisterPy()
Save it with any name.
Run it from python interpreter and Thats ALL!!

This problem mainly comes with 64 bit windows. download MySQL for python 64 bit on this link http://www.codegood.com/archives/129 and download MySQL-python-1.2.3.win-amd64-py2.7.exe (1.0 MiB)
This will install MySQL for python.
Windows 10 (64bit):
Indeed, I've had a similar issue and couldn't install the python 2.7 connector for MySQL.
Prior to this I've installed Python 2.7.15 with the Windows x86-64 MSI installer,
this was while I had Python 3 installed on my machine.
The Windows x86 MSI installer did the trick, I've installed it to override the previous version of Python 2.7.15, then installed the connector (this time it gave no error messages).
Then rechecked the status in the MySQL installer and voilà:

If you're still experiencing this with x64 or other python modules, I'd recommend this website Python Extensions for x64/x32

I had this problem because I use Python only from within SPSS. I resolved this problem by manually adding two registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Python\PythonCore\2.7\InstallPath
set to
C:\Program Files\IBM\SPSS\Statistics\24\Python
and
HKEY_LOCAL_MACHINE\SOFTWARE\Python\PythonCore\2.7\PythonPath
set to
C:\Program Files\IBM\SPSS\Statistics\24\Python\Lib
This easily fixed the issue on my previous as well as current laptops.

You need to make sure that you download the version with the correct "bitness" (32/64 bit), matching the "bitness" of your Python installation!
I ran into the same problem (with Python 3.7.2, though).
I had Python 3.7.2 32 bit already installed, but accidentally downloaded the 64 bit version of the MySQL Connector for Python 3.7.
When I tried to install the connector, I got the same error message:
Solution: I just downloaded the 32 bit version instead, and everything worked (installing the connector and actually connecting to the database)

In my case, I installed python 2.7.14 x64 only for my user. I have to look for this in my registry:
HKEY_CURRENT_USER\Software\Python
, export them, open the exported .reg file with a text editor, replace all occurrence of HKEY_CURRENT_USER with HKEY_LOCAL_MACHINE, and import it.
The result is: (remember to change the install dir to yours)
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\Software\Python]
[HKEY_LOCAL_MACHINE\Software\Python\PythonCore]
[HKEY_LOCAL_MACHINE\Software\Python\PythonCore\2.7]
[HKEY_LOCAL_MACHINE\Software\Python\PythonCore\2.7\Help]
[HKEY_LOCAL_MACHINE\Software\Python\PythonCore\2.7\Help\Main Python Documentation]
#="D:\\Desarrollo\\entornos\\python27_x64\\Doc\\python2714.chm"
[HKEY_LOCAL_MACHINE\Software\Python\PythonCore\2.7\InstallPath]
#="D:\\Desarrollo\\entornos\\python27_x64\\"
[HKEY_LOCAL_MACHINE\Software\Python\PythonCore\2.7\InstallPath\InstallGroup]
#="Python 2.7"
[HKEY_LOCAL_MACHINE\Software\Python\PythonCore\2.7\Modules]
[HKEY_LOCAL_MACHINE\Software\Python\PythonCore\2.7\PythonPath]
#="D:\\Desarrollo\\entornos\\python27_x64\\Lib;D:\\Desarrollo\\entornos\\python27_x64\\DLLs;D:\\Desarrollo\\entornos\\python27_x64\\Lib\\lib-tk"
And the installation afterwards is smooth as a breeze. Viola!

I solved this problem by using 32bit python

How to tell if rosetta is installed?

I am working on a Python script that will rely on rosetta being installed. Rosetta is a dynamic binary translator for Mac OS X which allows many PowerPC applications to run on certain Intel-based Macintosh computers without modification. Is there anyway for to check the OS to see if rosetta is there?

Haven't got rosetta installed anymore but if I recall correctly it would give some kind of usage screen if you just type translate (rosetta command line). If so, something like this should work.
if os.system("/usr/libexec/oah/translate > /dev/null 2>&1"):
print "Not installed"
else:
print "Installed"

If you are really just trying to check whether something with a PPC dependency will likely run, you could do a loose check that the running CPU type is PPC or the running OS X version >= 10.4 and < 10.7 since those are the OS X versions where Rosetta is supported and, at least on 10.6, OS X will automatically prompt the user to install Rosetta when needed if it wasn't already installed. Note that the Darwin kernel versions are different from the OS X version number, i.e 10.4 -> Darwin 8, 10.5 -> 9, etc.:
>>> import os
>>> os.uname()
('Darwin', 'kitt.local', '11.4.0', 'Darwin Kernel Version 11.4.0: Mon Apr 9 19:32:15 PDT 2012; root:xnu-1699.26.8~1/RELEASE_X86_64', 'x86_64')
>>> un = os.uname()
>>> darwin_major_version = int(os.uname()[2].split('.')[0])
>>> cputype = un[4]
>>> can_run_ppc = cputype.startswith('ppc') or (darwin_major_version > 7 and darwin_major_version < 11)
>>> can_run_ppc
False

There is no official way to get this.
Rosetta works via a program called /usr/libexec/oah/translate. Officially, this is an implementation detail which is subject to change, and therefore shouldn't be relied on. However, we know that it never did change until 10.7, when Rosetta was killed completely, so it's safe despite the caveats. Maria Zverina's answer works for that (if you add the path), and it's probably the simplest. Or, maybe, just check for the presence of such a file instead of running it.
Alternatively, Rosetta came with Intel 10.4-10.6 (earlier versions of the OS were PPC-only and didn't have Intel). Again, officially you're never supposed to rely on OS version, instead using the appropriate APIs to check for features. But in this case, there don't seem to be any appropriate APIs, so maybe this is appropriate. Except for the caveat that you don't have to install Rosetta with 10.6, so this won't detect users who turned off the checkbox. If you want to do this:
import platform
release, versioninfo, machine = platform.mac_ver()
versionbits = [int(bit) for bit in release.split('.')]
rosetta = (versionbits < (10,7) and not machine.startswith('ppc'))
(Note that this is also "bad" because on some versions platform.mac_ver() does some hacky stuff that you're not supposed to do—the right way to get the OS X version bits is to call Gestalt. But mac_ver() is part of the standard library, so at least you can rely on it doing the hacky stuff as well as possible, and it being widely tested.)
If you're not actually after Rosetta, but whether you can run PPC either natively or via Rosetta, that's even simpler. All pre-10.7 versions that don't come with Rosetta are PPC; all 10.7+ versions can't run PPC period. So, just "release < '10.7'" does it. (Again, with the caveat that 10.6 can optionally skip Rosetta install.)

Try to run:
brew config
Rosetta 2: true

Python REPL tab completion on MacOS

Before upgrading to lion, I had tab complete working in a python shell via terminal. Following these instructions, it was possible to have tab complete working.
Since upgrading to Lion, I am now unable to get tab complete working in a terminal session of Python. I've followed the above instructions to the letter, and it still does not work.
Is there a difference with the readline module in Lion? Hooking in to the 'tab:complete' option no longer seems to work. I'm wondering if it is terminal that is ignoring readline, or if it is python itself.
Python version: 2.7.1
Edit:
By tab complete, I mean I could do something like the following:
# django
import MyModel
MyModel.objects.a[TAB] # will complete to all()

Apple does not ship GNU readline with OS X. It does ship BSD libedit which includes a readline compatibility interface. The system Pythons shipped by Apple and the 64-bit/32-bit Pythons from python.org installers are built with libedit. The problem is that the commands supported by libedit are completely different from those of readline (see for example the discussion here). The traditional 32-bit-only python.org installers do use GNU readline as do some other 3rd-party distributors of Python for OS X, like MacPorts. Chances are that you were previously using such a Python and not a recent Apple one. You do have a few options, besides modifying Django: you can install the third-party replacement readline module; or you can use another Python that comes with GNU readline. However, you should not use the python.org 32-bit-only Pythons on 10.7 because, unfortunately, Xcode 4 on 10.7 no longer includes gcc-4.0 and the OS X 10.4u SDK which those Pythons need to build and install packages with C extension modules.
Putting the following in the python startup file will enable tab completion for both the libedit interface and the typical readline module. For more information on the python startup file, see here
import readline
import rlcompleter
if 'libedit' in readline.__doc__:
readline.parse_and_bind("bind ^I rl_complete")
else:
readline.parse_and_bind("tab: complete")

As it uses libedit/editline, the syntax to enable autocompletion is a little bit different.
You can first force emacs bindings (as it is with readline if I'm not wrong) by typing :
readline.parse_and_bind("bind -e")
Then you can add autocompletion linked to your TAB button (man editrc) :
readline.parse_and_bind("bind '\t' rl_complete")
And if you want to support indenting and has a history (found on internet), it should look like that (unless I made a mistake) :
import readline,rlcompleter
### Indenting
class TabCompleter(rlcompleter.Completer):
"""Completer that supports indenting"""
def complete(self, text, state):
if not text:
return (' ', None)[state]
else:
return rlcompleter.Completer.complete(self, text, state)
readline.set_completer(TabCompleter().complete)
### Add autocompletion
if 'libedit' in readline.__doc__:
readline.parse_and_bind("bind -e")
readline.parse_and_bind("bind '\t' rl_complete")
else:
readline.parse_and_bind("tab: complete")
### Add history
import os
histfile = os.path.join(os.environ["HOME"], ".pyhist")
try:
readline.read_history_file(histfile)
except IOError:
pass
import atexit
atexit.register(readline.write_history_file, histfile)
del histfile