Dd-wrt and asterisknow

copied and pasted from dd-wrt forum because i’m fairly sure the problem is on the routers side, but thought i should ask here as well

hardware: linksys wrt54gl running ddwrt v23 sp2.
my asterisk box is a 4 line (tdm400p 4fxo card) asterisknow setup that works great internally, making and receiving calls.

now here is the problem, i went to setup the router so that remote locations could access their sip accounts as needed and make and receive calls. anyway no matter what i do voice does not work on phones over the wan. I know this is a simple port problem but i can not figure it out. I have forwarded the correct ports and even went as far as setting up the asterisk box as a dmz, and even that did not work. if anyone has any suggestions on what to do or if a different firmware is needed please let me know.

thanks for any help