I got the following error message when trying to open a network interface for capture using Wireshark on Mac OS X (Wireshark 1.5.1 Intel 64 beta and 1.4.6 Intel 64 show this behaviour):
There are no interfaces on which a capture can be done.
To solve the problem open a Terminal and enter
sudo chown $USER:admin /dev/bp*
This command fixes the ownership of your Berkeley packet filter devices
/dev/bpf0 etc. which makes them readable and writable.
If you are using Linux instead of Mac OS X
When using a Linux distribution (such as Ubuntu, Debian, Fedora, Arch etc.) you can usually solve this problem by running Wireshark as root user (using
sudo wireshark). Alternatively set the permissions of your network interfaces to allow access by regular users).