Hi team, right off the bat I'll start by admitting that I've done something stupid!

Last week we had no end of problems with our Internet connection.  By coincidence we'd been having power cuts (Vector's problems) and faults with our UPS at the same time as the problems with the Internet connection.  With everything seeming to be going wrong all at once, I didn't stop to think things through when our ISP wanted to swap out our modem/router.  I put the new modem/router in (identical to the old one), it did not resolve our Internet issue, and sent the old modem/router back.  That was the really stupid part.

Several days later our ISP had finally resolved the Internet problems and I had resolved the UPS issues.  With everything now back to normal I wanted to copy some photos onto our NAS (the little known but actually pretty good value for money Toshiba Conviohome).  Grim.  Nothing on the network can see the NAS.  Can't open a browser to its IP address or name any more either.  NAS appears fine, HD and network LEDs blinking away happily.  Its just invisible to everything on the network.

Its at that point I remembered that I'd given the NAS a fixed IP address a year or two earlier, I think because occasionally the router's DHCP server would change the NAS' IP address rather than renew it when its lease expired.  I remember logging into the settings on the NAS and specifying the fixed IP address.  I also remember logging into the router and allocating the specific IP address to the NAS' mac address.  I know the specific IP address:  192.168.20.7.  If I changed any other settings on the router I (most inconveniently) no longer remember!  No idea why I used a fixed IP address in the 192.168.20.x range rather than the usual 192.168.1.x range.  If I had to guess my thinking was probably to give storage and similar devices slightly different IP addresses so that it was immediately clear that they are not phones, tablets etc.

Hoping that I might be able to sort this with a couple of basic tweaks I logged into the new router, added the fixed IP and mac address into the Static IP Lease List and changed the subnet mask from 255.255.255.0 to 255.255.224.0 so that the NAS' fixed IP address fell within the range of addresses allocated by the router.  I really thought that this would be all I needed to do to be able to see my NAS on the network, but no luck at all.  Restarting other devices on the network, yanking the power cable from the NAS forcing it to restart and waiting a few days to see if the NAS checks in with the router for changes have not made any difference either.

I'm hoping that someone with signficantly better knowledge of networking fundamentals may be able to identify what I need to do to get this plucky little NAS visible again on our home network!  Any assistance gratefully received!

The NAS does have a reset button but I'm quite reluctant to use it in case it affects the content as well as the settings.  It also has a USB port which although I've never used I presume would enable me to plug it directly into a PC and treat it like an external hard drive.  So worst case scenario I could just copy off the NAS contents, get a new NAS and then copy it back.   Best case scenario though would be to get the NAS back on the network!