POAs in your GroupWise® system should be located behind your firewall. If GroupWise client users want to access their GroupWise mailboxes from outside your firewall using the Windows client or the Cross-Platform client, you should set up a proxy server outside your firewall to provide access, as described in Section 36.3.1, Securing Client/Server Access through a Proxy Server. WebAccess client users access their GroupWise mailboxes through their Web browsers, so your Web server handles the access issues for such users.