Can't login when device has hostname six or fewer characters long

[tdev]

I have two Asus RT-N66Us both with 380.70. They get their IPs via DHCP. On the DHCP server, which is also the DNS server for the local network, I gave them their IP addresses and the hostnames wap1 and wap2. I then went to:

http://wap1/

...and attempt to login. After submitting user and pass (whether right or wrong), I was redirected right back to the login page.

This didn't happen when you access them via IP address, i.e. http://192.168.x.y/. So after some experimenting I figured out that this would happen whenever the devices' hostnames were six characters or less. Trying to login to http://abcdef/ didn't work and just redirected back to the login page, but http://abcdefg/ worked fine.

Is there a reason for this, is it a bug that's gone unnoticed, or have I done something wrong I haven't figured out yet?

 

[tdev]

I discovered that logging in when the device has a hostname 6 characters or less works if you follow the hostname with the local domain, e.g.:

http://wap1.mydomain.com/

Whereas, as stated before, you can't login here:

http://wap1/

And trying to get around it by logging in at the first address and then going here:

http://wap1/index.asp

...redirects you to the login page.

Anyone?

 

[kfp]

Purely speculation, but I think it’s because the HTTP header ‘Referer’ is too short.
When you navigate to http://abcde, httpd would redirect you to the login page with ‘Referer: abcde’, and there’s probably a check for it and only accepts domains longer than 5 chars, as to why, I don’t know.

Edit: you can test this by navigating to http://wpa1/index.asp but with a browser extension to overwrite the ‘Referer’ header with 12345 and 123456

 

[tdev]

Turns out this isn't a problem in the LTS fork, so I'm all set.