>>From the looks of the LinkSys KB, they use the term Port Triggering.
>
>Yup, I've tried both adjusting the MTU and port triggering (just tried it again). When >I send an email to myself I get the same "550 recipient unknown".


Evan,

Check to see if there is an option for SPI (Stateful Packet Inspection). Try it with that option cleared (if it's checked). Judging from some of the Linksys SPI searches on Google, it can cause problems...


- Brian