Problem with user authentication

["Stellwag, Christian" <cs...@emsw.de>]

I've got a Tomcat 3.2 running with standard form-based user authentication
for my context.
It works fine when accessed from within our Intranet.

But I get a login-error after authenticating when accessing the site from
the web as if I typed in a wrong password.

The server is connected directly to our provider.
I don't know the exact configuration at our provider's location. 
They do something like NAT, and letting only specific IP-Adr. + Port#
through. 
In this case its P# 8080 where HTTP-service listens to.

What's wrong ? Do we have to grant access to another port ?

Thanx 4 your help, Chris



additional info :

tomcat-users.xml contains user information and
web.xml contains :

    <web-resource-collection>
      <web-resource-name>Protected Area</web-resource-name>
      <description></description>
      <url-pattern>
        /servlet/*
      </url-pattern>
      <url-pattern>
        *.dsp
      </url-pattern>
      <http-method>
        GET
      </http-method>
      <http-method>
        DELETE
      </http-method>
      <http-method>
        PUT
      </http-method>
      <http-method>
        POST
      </http-method>
    </web-resource-collection>
    <auth-constraint>
      <role-name>
        isupport
      </role-name>
    </auth-constraint>
    <user-data-constraint>
    </user-data-constraint>
  </security-constraint>
  <login-config>
    <auth-method>FORM</auth-method>
    <realm-name>Example Form-Based Authentication Area</realm-name>
    <form-login-config>
      <form-login-page>/login/login.jsp</form-login-page>
      <form-error-page>/login/error.jsp</form-error-page>
    </form-login-config>
  </login-config>
  <security-role>
    <role-name>isupport</role-name>
  </security-role>