Most redirects from one URL to another are implemented on the server and return a 301 server response code, which signifies that the page has been moved permanently to a different URL. It is helpful, however, to be able to very that your request for an old URL is in fact returning a 301.
The alternatives to serverside redirects are JavaScript or meta-refresh redirects that occur within the page’s source code as it’s loaded into the browser. These options return a 200 response code, which signifies a regular request and response.
301 redirects on the server are usually the advisable option both for search engine optimization and for Web analytics.
Search engine spiders correctly follow 301 redirects and index the new page, whereas they cannot dependably interpret either of the browser-based techniques. If no page exists at the old URL anymore, the 301 redirect is the only option for avoiding broken links. (This is of course as important for user experience as for SEO.)
For Web analytics, the browser-based options run the risk of executing the tracking code and registering a pageview for a page that the visitor never sees.
To check the server response code, you can refer to the Network tab of the Developer Tools panel in Chrome, or you can use a quick and easy Web utility such as Rex Swain’s HTTP Viewer.
