I've been buying these for a while and have quite a few of them which is unfortunate for me but offers the benefit of some longer term insight and perhaps will allow me to steer others away from this. While at first glance they might appear to work without any issues over the long haul mysterious issues and lack of fixes for what seem like firmware issues prevents me from recommending this.
First, if you try configuring these across a WAN, when they pickup an address via DHCP they will not be visible across the WAN at all. It doesn't appear that it properly uses the default gateway until a manually assigned address is made. This can be done easily through the web interface from a local device. Getting an initial address from DHCP does simplify the config via web browser however which is what prevents it from getting 1-star.
Secondly, it apparently, with UPnP configured, continues to grab a DHCP address even if an address is manually assigned. I don't care for this but you can disable UPnP to prevent this.
Third, you CANNOT reset this to factory defaults or fix a botched config. This is unforgivable. I've had instances where this box is mixed up with another and both were configured already and you can't just reset and start over.
Finally, mysterious issues appear when printing across a WAN. It'll accept jobs but won't print them. I've not been able to resolve this and it has only recently cropped up on a regular basis. I've had this issue in the past but only sporadically but new routers and network gear has seemed to bring this issue to the forefront.
I'd recommend TRENDnet 1-Port Parallel Print Server TE100-P1P as an alternative. I've placed a few of these into situations that were problems with these DLINK units and the problems have all gone away. The TrendNet however doesn't self-configure via DHCP which is unfortunate. The Trendnet unit is less expensive too.
Keep in mind that these and other parallel boxes are ancient by today's standards. Firmware updates are non-existent and most have firmware dated from 2003 or 2005.