Re: [users@httpd] self-referential URL's and load balancer

Sander Temme <sctemme@xxxxxxxxxx> · Sat, 17 Jun 2006 10:17:11 -0700

Hi enigma,

On Jun 12, 2006, at 1:53 PM, enigma wrote:

I have a problem with the self-referential URL's being generated by  

Apache

when a hardware load balancer is front ending it.

This is a well-known problem with load balancing and SSL offload in  

front of any web server. The httpd simply doesn't know that HTTPS  

exists in front of it, and can not generate the correct Location:  

headers for Redirect responses.

Some load balancers have built-in fixups for outgoing response  

headers. You can use those to repair the Location: headers as they  

are sent to the browser. See your load balancer documentation,  

support community or your favorite SE to set this up.

Which version of Apache are you using on which platform? The trunk of  

Apache now has support for setting the scheme in the ServerName  

directive, so you can go

ServerName https://myserver.foo.com

with optional port. You can see the code at:

http://svn.apache.org/viewvc?view=rev&revision=399947

That should go a long way towards fixing your issue, especially if   

everything you do happens inside the web server. And, any module that  

plays nice and calls the http_scheme hook should get the correct  

information.

I have proposed to backport this to Apache 2.2, and a version of the  

patch that applies to the 2.2.x  branch is at:

http://people.apache.org/~sctemme/servername_22x.patch

Unfortunately, httpd 1.3 hardcodes this scheme information so this  

approach will not work. the EAPI patch at least makes it settable,  

but you only have that if you have mod_ssl.

https://www.example.com/test/

I have tried setting UseCanonicalName Off without success. I can  

remap the

port with the port directive, but it still changes the https to http.

UseCanonicalName Off should help with the port value, but not the  

scheme.

You mention the Port directive, which disappeared in httpd 2.0 so  

that means you're using 1.3. As I said, the ServerName [scheme://] 

hostname[:port] code does not work with that version, so unless you  

can upgrade you'll have to fix this on the Load Balancer.

S.

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sctemme@xxxxxxxxxx            http://www.temme.net/sander/
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