Fix for header IP with source port

[AnythingOverIP]

NetBox version

v3.6.4

Feature type

Change to existing functionality

Proposed functionality

Based on a Slack Discussion, I'm submitting what could be a half bug / half feature request/issue...

When NetBox is behind an IIS reverse proxy, it appears that the header information is different. We can use it without any issue, except if a user enter a wrong credential set, which results in an error message:

The user IP returned has source port, which breaks the get_client_ip function defined in netbox/utilities/request.py

I worked around the issue by adding a single line of code:
client_ip = client_ip.split(':')[0] just before try

Use case

To prevent error message, which lead the user to think that server is down instead of him entering a wrong password.

Database changes

none

External dependencies

none

[candlerb]

Unfortunately this breaks when given an IPv6 address, including an IPv4 mapped one like ::ffff:192.168.6.2 - see discussion #14307.

Proposal:

• if the IP address contains only a single colon, then it can't possibly be an IPv6 address, so you can do the IIS workaround (urgh).
• if the address looks like [addr] or [addr]:nnn then strip the port and the brackets. This is on the assumption that if IIS were ever to add a port to an IPv6 address, it would have to wrap it this way
• otherwise, leave it alone