I posted this in the Shareport forum, I hope it helps.
I went into the setup under network settings and unchecked the "enable DNS relay" box and then reset the router. Shareport has stayed connected and I have been able to print for 5 days without a reset. Shareport has never stayed connected for more than a few hours before. I did this on a suggestion in another forum to get my Directv TV Apps to work with my D-Link dir-655 router. It fixed that problem and also fix my problem with shareport. I hope this helps others fix their shareport connection problem.
I visited dslreports.com.
Many people said unchecking 'enable DNS relay' fixes the connection drop.
Based on how the function works,
the firmware program doesn't seem to correctly free the memory in 'DNS relay' function, I guess.
Thus, it might fix the shareport problem -- shareport works just after rebooting but fails after
a while -- too.
Let me try your suggestion, and let you know if the remedy fixes the shareport problem.