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Subject: Proxying to dynamically changing origin servers
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From: Rene Mayrhofer <rene.mayrhofer@fh-hagenberg.at>
Date: Mon, 29 Aug 2011 11:30:01 +0200
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Message-ID: <201108291130.01459.rene.mayrhofer@fh-hagenberg.at>

Hi everybody,

[Please CC me in replies, I am not currently subscribed to this mailing 
list.]

For a research project, we currently have an interesting problem to 
solve: to connect HTTPS clients to dynamically changing, internal HTTPS 
servers. One approach that we are currently evaluating is to use a 
publicly accessible HTTP proxy with CONNECT support to "tunnel" the 
HTTPS connections to the internal servers. However, the internal 
addresses may change dynamically. The question is therefore if Traffic 
Server can be configured to (or if it is easy to write a plug-in to):

a) be used in "normal" proxy server mode for clients with explicit proxy 
server configuration to use the CONNECT call for some HTTPS URLs; and

b) for the origin server resolving to be done dynamically based on 
internal look-up tables. E.g. the URL 
https://my-example.local.com/whatever specified by any client in the 
CONNECT request should be mapped to host 10.20.30.40 (the HTTPS server 
may use my-example.local.com as its server address, but the IP will 
change dynamically).

I am aware that this is a mix between reverse proxy functionality 
(mapping to internal servers) and normal proxying (CONNECT to 
client-specified, different URLs). Based on the SDK documentation, I am 
also unsure which kind of plug-in would be required to make this work. 
The backup plan is to use a "normal" proxy with dynamic DNS for 
resolving the internal IP addresses, but we would like to avoid this 
complexity if possible.

Are we on the right track and is this possible with Traffic Server?

best regards,
Rene