roaming users problem

[Ron Chan]

Can anyone help?   We have vpopmail installed and running for the last 8 months with multiple domains and many roaming users   95% of the time it works fine - however, every now and then, users get the "domain isn't in my allowed rcpthosts" message when they send, if they press send again 2 or 3 times, it eventually goes   The only reason I can think is that the user would connect to their isp, pick up email, write email offline, the connection is automatically disconnected (either thru timeout or setting in the email program), when they get back on to send they are assigned a new ip address - hence they are no longer authenticated to send mail   If this is so, does anyone know a way round this?   Many thanks in advance Ron