IPv6 Address to supply for Python socket source

Question

I've set up a VM and am trying to use a Python script to send IPv6 messages to my computer so I can analyze it using WireShark. The host computer is Windows, and I want to see messages from a Linux VM. However, when I try to send messages, socket.bind() returns with an invalid argument error. What IPv6 address should I use as the local IP for binding sockets? I'm 99% sure that the error is coming from binding to an invalid IP. So what should I use as the IP? Here is the output of nmcli dev show, hopefully this is enough information to help me figure this out. If it's not, let me know and I'll add more info.

[eng@peter test_scripts]$ nmcli dev show
GENERAL.DEVICE:                         enp0s3
GENERAL.TYPE:                           ethernet
GENERAL.HWADDR:                         08:00:27:F7:9A:17
GENERAL.MTU:                            1500
GENERAL.STATE:                          100 (connected)
GENERAL.CONNECTION:                     System enp0s3
GENERAL.CON-PATH:                          /org/freedesktop/NetworkManager/ActiveConnection/0
WIRED-PROPERTIES.CARRIER:               on
IP4.ADDRESS[1]:                         10.0.2.15/24
IP4.GATEWAY:                            10.0.2.2
IP4.DNS[1]:                             10.0.2.3
IP4.DOMAIN[1]:                          stc.syrres.com
IP6.ADDRESS[1]:                         fe80::a00:27ff:fef7:9a17/64
IP6.GATEWAY:

GENERAL.DEVICE:                         lo
GENERAL.TYPE:                           loopback
GENERAL.HWADDR:                         00:00:00:00:00:00
GENERAL.MTU:                            65536
GENERAL.STATE:                          10 (unmanaged)
GENERAL.CONNECTION:                     --
GENERAL.CON-PATH:                       --
IP4.ADDRESS[1]:                         127.0.0.1/8
IP4.GATEWAY:
IP6.ADDRESS[1]:                         ::1/128
IP6.GATEWAY:

I've tested 'fe80::a00:27ff:fef7:9a17/64', 'fe80::a00:27ff:fef7:9a17' and others, but still can't get it to bind. What IPv6 address should I use?

Answer 1

If you want to listen, your best bet is to bind to :: which is the equivalent of binding to 0.0.0.0 .

If you want to connect to that server, keep in mind you are using link-local addresses, which require a scope ID in order to function properly.

For example, on Linux, to connect to host fe80::1 on interface eth0 you would connect to fe80::1%eth0 . If you're dealing with the socket module, don't forget to either use getaddrinfo() or be very careful to populate scopeid .