show html page when connection is unavailable
 

Hello,

on my linux router I need to show custom offline html page when Internet connection is unavailable. What is the best way howto do it? I would like to also use some simple proxy server like tinyproxy.

Thank you in advance for your suggestions.

No idea, since you don't tell us anything about your router.
Ok...so install tinyproxy. We can help with errors and problems, but just saying what you'd LIKE to do isn't either. Tinyproxy has a lot of tutorials and documentation you can easily find.

The router is a standard Linux PC with two ethernet cards.

I have tiny proxy installed already. The question is if some options allows to show the offline html page when internet connections is unavailable?

Thank You

...which says nothing about how you have it configured to BE a router. What software are you using? And you do know the difference between a router and a proxy server, right?
If you already have tinyproxy installed, why ask about it? If you want your own web page to be returned when a page can't be found, read the man page for tinyproxy.conf:
http://linux.die.net/man/5/tinyproxy.conf

...pay particular attention to the ErrorFile directive. Example:
http://blog.macrowen.com/m/?post=69