topic Re: Style sheets not loading in NAT environment in Network Security

Style sheets not loading in NAT environment

Erik Molenaar — Mon, 11 Mar 2019 20:02:14 GMT

Hi all

We have users that want to use a website www.watwaswaar.nl that uses stylesheets. But the users that are behind our NAT firewall are not able to view the web pages as they should be.

I found out this could have something to do with NAT, but does anyone have a clue what i should look for in the firewall rules that blocks these from loading?

Best regards

Erik

Re: Style sheets not loading in NAT environment

PAUL GILBERT ARIAS — Mon, 07 Mar 2011 16:35:24 GMT

I haven't heard about similar issues but we can try to assist.

Have you check your logs while trying the connection to that site?

How you have your NAT configuration? using PAT?

Re: Style sheets not loading in NAT environment

csaxena — Mon, 07 Mar 2011 16:37:30 GMT

Hello Eric,

If i am not wrong, a website hosted on inside of firewall loads fine from inside and for outside world the style sheets are not loading. Probable reason for this could be that the style sheets are loading using the private IP of the server and not the public IP or the public address is not translating on ASA. Please reply back with source code of the website if you are not able to get to the root cause.

Also, to troubleshoot this further, taking captures on inside workstation and outside workstation will help.

Hope this helps. Please reply if you need further assistance.

Regards,

Chirag

P.S.: Please mark this thread as answered if you feel your query is answered. Do.rate helpful

Re: Style sheets not loading in NAT environment

Erik Molenaar — Tue, 08 Mar 2011 13:16:09 GMT

Hi Paul and Chirag,

Thanks for your reply. I found out that it's not NAT/PAT that is blocking the style sheet from loading because we have other connected NAT/PAT and non-NAT/PAT networks where this actually does work.

So much for the subject of this post!

Done so far:

- made captures of successful and unsuccessful tries, thru SPAN and on the FWSM

- worked through the FWSM's access lists for any strange rules

- looked in the logging of the FWSM

- issued 'show connection local etc.'

Not much from that. Perhaps a closer look at the 'deniy'messages in FWSM logging sheds a light...

Firefox error console reports: The stylesheet http://www.watwaswaar.nl/view/map/ was not loaded because its MIME type, "text/html". is not "text/css".

That's a funny message. It almost suggests that the error is in the style sheet itself. But then why does it work as mentioned, on other networks on the same FWSM?

Re: Style sheets not loading in NAT environment

Erik Molenaar — Mon, 21 Mar 2011 10:00:41 GMT

Hi,

After some testing it turned out that teh ISP where the website is hosted had blocked one of our NAT global addresses.

Thanks all for your support!

Erik

Re: Style sheets not loading in NAT environment

csaxena — Mon, 21 Mar 2011 15:33:28 GMT

That's great news Erik. We should have thought of this at first place. Glad it is working. Please mark it answered for other to refer in future.

Cheers,

Chirag