Making a whole site website SSL (https)

[BigMiniMan]

Our IT department wants to make a change to our website and serve all the pages under SSL (https).

This will be happening at the same time as a move from classic ASP to ASP.Net so the file extensions for non re-written urls will change (this doesn't equate to many).

They will be ensuring everything is 301 redirected correctly.

Even with this I can't help being very nervous about the change.

We have tens of thousands of links to the website gained over many years, and I understand even with 301'ing them they will lose some of their value. We receive tens of thousands of natural visitors per day.

Has anyone done anything like this before, or have any advice on whether it is the right thing to do?

[Dr-Pete]

I think Highland covered the basics - it will be seen as a sitewide URL change, so you need to make sure those 301s work. You could lose some small amount of link-juice, and expect rankings bounce in the short-term (although it should recover 98%). Also, it can add a lot of overhead to a site, so make sure your servers are up to it.

Technically, Google says it's fine. They don't treat secure pages any differently than "regular" pages. Practically, I'm not a big fan, to be honest - it's adding a layer of complexity. Still, there are big sites that are secure and rank fine.

[Highland]

https is treated just like a subdomain is. So your http site will be seen differently. 301s will be necessary.

SSL also adds some overhead and requires a bit more bandwidth (there's more negotiation involved). If your site is slow, this could make it slower.