(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")))))