We use RI on Windows 2000, 2 RI servers in the DMZ, each connected to a WM server inside our firewall. Loading is fairly light, as most partners use FTP or SMTP for integrations.
We had some initial problems with RI connections failing, but have resolved by scheduling
(1) wm.server.security.revInvoke:keepAliveConnections, running every minute.
(2) a custom service running every 15 minutes to detect and restore failed connections, using services wm.server.security.revInvoke:listRegisteredConnections,
wm.server.security.revInvoke:deleteConnection,
wm.server.security.revInvoke:registerReverseConnections.
HTH
#Integration-Server-and-ESB#webMethods#webmethods-Protocol-and-Transport