Right, We have a draytek 2800g router at our office in bolton, everything works ok apart from users with exchange email accounts. pop email, internet access and lifesize video conferencing all work ok. I had this problem before and fixed it and now the router has been reset and i cant remember the fix! it was something to do with having the lifesize vc kit on its own ip and opening ports and port redirection/dmz zones, we made a change to that kind of setting to get it work. any thoughts, first time forum user so if you need more info please let me know.

Exchange uses SMTP mail which requires Port 80 to be opened.

Port 25?

Oops, thank you. Quite correct - port 25. I'll blame it on my dyslexic keyboard.

thanks for the response, should you need to manually open up port 25? we have a virtually identical setup at another office which doesnt get this problem. the issue is with sending emails, receiving seems to be ok, sorry should have included that in original post.