Can https content ever be cached at CDN datacentres? - ssl

I know that modern web browsers cache https content by default. But when you use, say, CloudFlare on your https webpage can it ever cache the css/jpg files for the client? I'm expecting the answer is no as its encrypted, but maybe the datacentre is intelligent and can establish its own connection as a client, cache, then serve as a proxy or something using its own certificates. Thanks

Cloudflare is a content delivery network and not a simple load balancer. Because it is expected that they reduce the load on the original server they will cache also https traffic. This means that they will be a man in the middle and provide their own certificate for the site. For more information see their SSL-FAQ.

Related

How to prevent SSL Proxying for https site?

I'm serving my site through nginx. For securing it, I have added ssl certificate and made it compatible with https protocol.
Now when I do request data from the site through browser while keeping ssl proxying on, whole request body and response body are showing there, so there is some loophole in my configuration and if it's not a loophole, I want it to be like giant company's site - facebook, apple etc. Where these ssl proxy tool can not parse the request and response.
If the client doesnt explicit show itself as a proxy (aka via X-Forwarded headers), is very hard to know for a server if any connection establishes proxied, Of course, out there are sophisticated methods to find these connections, like blacklists with common proxy sites, AI traffic algorithms, etc. but you will need massive amounts of data (that giant companies have) or specialized traffic services like cloudflare.

Is CloudFlare's free SSL actually secure?

I've just set up CloudFlare on my web app. The free version, since my app isn't generating any revenue right now.
Now all my traffic is routing through CloudFlare's servers, correct? And that connection is "secure" because it's under HTTPS -- Chrome even displays the green padlock.
But CloudFlare is still communicating with my server over HTTP (unsecure connection), are they not?
Doesn't that mean all my client's data is sent in the clear between CloudFlare and my server? And that makes it not really secure at all, despite what Chrome thinks?
No.
The "Flexible" option of the "Crypto / SSL (with SPDY)" setting is not secure. If you read the "Help" text it says:
There is an encrypted connection between your website visitors and CloudFlare, but not from CloudFlare to your server.
You must install an SSL certificate on your own server and then select the "Full SSL (strict)" option to be secure.
You can configure the origin for the CDN (i.e. your servers that provide the original version of the content to be distributed across the CDN) to provide data using HTTPS. With the pro version (which you are not currently using) you can also use the SPDY protocol. HTTPS communication between the CDN and your servers protects that part of the communication path.
Additionally, and optionally, you can use Authenticated Origin Pulls (also available in the free version) to ensure that the CDN and origin (you) are both who you claim to be.

Cloudfront in front of an IIS7.5 web server with SSL

I have a CloudFront destro in front of my asp.net application, serving dynamic content. All cache periods are set and everything looks ok.
I am using cloudfront mainly to accelerate the site for international visitors.
I have a registration page on the site that uses SSL. I understand that I can't use my own SSL with cloudfront, but is there a way that I can tell cloudfront to point the user to the origin when they navigate to one of the HTTPS pages?
The urls on your secure page must use the https prefix or the browser will complain about mixed-mode content. This means that the requests have to start their lives as https ones. This makes redirection in the manner you suggest impossible.
Your best bet is to have logic in your pages that determines the host portion of your url and protocol so that if it's a secure connection, all your content urls are prefixed with the secure host/protocol in the form https://[cloudfront-secure-hostname]/[your content]
If the connection is not secure, you return your standard CDN hostname using http.
The only down side is that a user will see requests going off to a domain other than yours. This shouldn't be too much of a problem though.

Would it be wise to serve static content on a cookie-free domain in SSL?

I have long read about "Use cookie-free domains" aka create a subdomain that can serve css, js, and images, all in 1 subdomain.
However 99% of our site is served via ssl, and ssl certificates can be expensive.
And so if we did this cookie-free subdomain, and to avoid that error that says "This page contains both secure and nonsecure items" error, we'd have to have ssl on the cookie-free subdomain.
Have any of you done similar things?
Would it really be worth the cost, to setup a 2nd ssl subdomain to host all the css, images, and javascript for all of our sites?
Thank you.
No.
If you use HTTPS, you can probably also use HTTP/2, which avoids re-sending cookies unnecessarily, so the problem goes away.
There's a significant cost of opening a new TLS connection to a domain for the first time, so the more domains you use, the more first-connection overhead you pay for.
Unless your cookies are very large or you have lots and lots of requests, then the cost of establishing an additional TLS connection is likely to be greater than the cost of sending cookies on an already-open connection.
BTW: when using HTTPS be sure to add an HTTP header that explicitly allows caching (e.g. Cache-Control:public, max-age=604800), because otherwise browsers may not cache anything and waste bandwidth re-downloading files over and over again.

Is using a CDN possible when you're running a HTTPS website?

I have a website with only home page available through simple HTTP protocol.
All other pages are accessible only through HTTP over SSL(https://).
I'm using CDN for home page and very happy with it.
But for me it looks like using CDN for https pages is impossible because of security warnings, especially in IE. My files hosted at CDN are accessible though simple HTTP protocol.
What should I do? How this problem can be solved?
You need to get a CDN that supports serving files over HTTPS, then use that CDN for the SSL requests.
You can do this if their boxes have HTTPS support. What you can't do is use a subdomain of your own domain to cname against the cdn network. Because SSL doesn't work this way.
so https://cdn.tld/mydomain/path/to/file as a mechanism does work (because browsers will verify the cdn.tld ssl certificate correctly)
but https://cdn.mydomain.tld/path/to/file will not.
Two options, but in general I'd redirect all pages that don't need to be SSL'ed to their non-SSL equivalent and only use SSL when necessary.
Get a SSL certificate for your CDN host. It's just 30 bucks/year, but you need to take into account that this requires more configuration and depending on the traffic, this is also more expensive because the server requires more resources for SSL'd connections.
For the relevant pages, store the CSS/images/js files "local" on your own SSL host and use them when you need SSL. Of course you loose the speed etc. from the CDN, but that's a trade off. We opted for this because just our signup is SSL, 99.9999% of the time users spend on our website is on non-SSL links.