When dealing with http servers and SLB, it's common to have redirects, but you need to understand the differences.
Typically 301 and 302 are the most used redirect methods. 307 is another redirection but not seems that often. These are also called "Server Side redirect" since they typically in the past where used on web-server daemons but in reality they could be servers, WAF or reverse-proxies.
Let's look at some redirects examples , but before we do that, " what are redirects"? These are populate Location: headers that re-points the web client to the web content that he/she is looking for. The simple definition
A location is passed to the User-Agent in the shape and fashion of
Location: http://kenfelix.com/blogger/
Or
Location: https://kenfelix.com/
This new Location header is just that, a header that points you to the new location.
301 == permanent
302 == Found-A-new-Location
307 == temporary
NOTE: 302 are mistakenly called temporary redirects , but per the http.definitions, they are not.
reference https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
Here's my bank IBC, this is a very bad redirect flow. It just cause more additional work on the browser , and additional delay for the 1st byte served or the content requested
Up next here's another example of a redirect flow. I highlighted cookies in this one . Two window servers where involved plus a load-balance
note: notice how Set-Cookies are not encrypted, this leaks internal host information
One of the best unix tools available for following redirects is the unix curl with the -L option.
L == Locations
Here's mail.google.com, notice the URL protocol changes if you initially hit the 1st link via HTTP.
Each redirect creates a new HTTP.request and adds to the dependency and delay factor.
Typical a domain redirect are very popular;
e.g
And for SSL enabled site a http-2-https are commonly used
Jigsaw has a simple and effective 307 redirect and proper use ( notice temporary in the http.response code ?}
https://jigsaw.w3.org/HTTP/300/Overview.html
HTTP/1.1 307 Temporary Redirect <-----
vrs
HTTP/1.1 302 Moved Temporarily <-----
Here's how paypal redirects 302 then 301 (a big no no imho )
reference
http://www.redirect-checker.org/index.php
Good practices are ;
1: keep the redirects as small as possible
2: use 307 redirects when possible & if the target is Temporary and not Temporarily
3: avoid a redirect loop
4: if you redirect from HTTP 2 HTTPS on a server, try to use HTTPS on that server
5: check redirects consistency and remove any stale redirects on a regular basis
6: for web-developers, harvest your site URLs and run them thru a spider or URL optimizer that minimizes duplications a short HTTP hops between redirects on a local website
7: remember redirect types 301 are more favorable for SEO
These tips would help you in creating a good HTTP experience for the end-user
NOTE: PayPal is really cool if they see your a web-analyzer guy that uses curl , they give you a X custom header for jobs recruiting in the response
Ken Felix
NSE ( network security expert) and Route/Switching Engineer
kfelix -----a----t---- socpuppets ---dot---com
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