Emacs behind HTTP proxy

For w3m, this setting has worked for me:

(setq url-proxy-services '(("no_proxy" . "work\\.com")
                           ("http" . "proxy.work.com:911")))

I've got authorization working by:

(setq url-proxy-services
   '(("no_proxy" . "^\\(localhost\\|10\\..*\\|192\\.168\\..*\\)")
     ("http" . "proxy.com:8080")
     ("https" . "proxy.com:8080")))

(setq url-http-proxy-basic-auth-storage
    (list (list "proxy.com:8080"
                (cons "Input your LDAP UID !"
                      (base64-encode-string "LOGIN:PASSWORD")))))

Works for Emacs 24.3. It is based on non-public API tricks, so might not work in another Emacs versions...

Emacs populates the url-proxy-services variable from the http_proxy, https_proxy and no_proxy environment variables if they are set.

This is a bit old, but I had issues connecting as well. One thing I needed to do is add my certificate to the the gnutls-trustfiles in order to connect.

(with-eval-after-load 'gnutls
    (add-to-list 'gnutls-trustfiles "path/to/cert.crt"))
(setq url-proxy-services
   '(("no_proxy" . "^\\(localhost\\|10\\..*\\|192\\.168\\..*\\)")
     ("http" . "proxy.com:8080")
     ("https" . "proxy.com:8080")))