I have a DNS-323 and it works fine with my DIR-827. I don't see the DNS-323 on the router because I use a static IP on the DNS-323. I connect to the "server" from workstations by mapping the drive in Windows or mounting it in Mac.
I configured DHCP on the DIR-827 to use .126 to .199
That way I can use .2 to .125 for static IP's (e.g. printers, servers, DNS-323).
Alternatively you could reserve IP's but for the DNS-323. 6 or half dozen...