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Synology @programming.dev
NotNotMike @programming.dev

Connecting NAS to new network

I've had an issue with my router and had to replace it. Unfortunately, now my Synology NAS does not appear in the device list of the router or using Synology Assistant.

The server is connected using an Ethernet cable, so I would assume the reconnection would be automatic.

I have tried restarting the server, but it did not reconnect on successful boot.

I know it's still alive because I can hear the disks working on something, so the system is up.

Is there another way to restore connectivity?

Sounds like I may be able to connect the device to my desktop using an Ethernet cable, but to what end?

5 comments

  • I've never owned a Synology product. However:

    Unfortunately, now my Synology NAS does not appear in the device list of the router or using Synology Assistant.

    I'm assuming that both the prior and current network used DHCP, and that the NAS is configured to use DHCP. If you previously allocated a static IP address to your Synology NAS --- which I could easily see one doing, to keep it reachable on the local network by IP --- and your new router hasn't been set up to reserve a static IP address for your Synology NAS (or uses a different reserved IP address range than your previous router), you could have issues. Like, say the previous router used the 192.168.1.0/24 network, and the new one used 192.168.100.0/24; I have run into routers that have used different reserved Class C networks out of box.

    • I'm assuming that your router is listing outstanding DHCP leases that it's issued to connected devices. If the NAS isn't showing up in the router's Web UI, then it probably hasn't issued one to the NAS. DHCP requests go out as broadcasts on the network, so I'm guessing that unless your router has some logic to eat DHCP requests (given that it's running a DHCP server) all local devices should be able to see them; you could probably run tcpdump or wireshark on a Linux machine on the local network and see what is actually being sent when you boot your NAS. I don't believe that it should be able to see the response. http://www.tcpipguide.com/free/t_DHCPMessageFormat.htm
    • Many devices that have Ethernet ports have an LED that comes on to indicate whether the Ethernet-level link handshake has completed. Either the Synology device or the router might. If you aren't getting a link light, they can't handshake. Might try swapping out the cable.
    • If there's a traffic LED also on the port and you send a broadcast ping from a machine on the LAN (# ping -b 255.255.255.255 -i 0 will ping-flood the LAN with broadcast pings from a local Linux machine), it should result in a packet with an Ethernet broadcast address being sent to the Synology NAS, and the traffic LED should flash. If it doesn't flash, then there's probably an issue between the router and NAS at the Ethernet level or below, rather than at the IP level or above.
    • I assume that you don't want to do this, since I would assume that it may toss your data, but it sounds like at least some Synology devices have a reset button, which I expect would do a factory reset on the configuration.

    Sounds like I may be able to connect the device to my desktop using an Ethernet cable, but to what end?

    Well, if you do have the Synology NAS configured to use a static IP address and you have the thing connected to your desktop, you can hopefully see what traffic it's sending, which might indicate which static IP address you have the Synology device configured to use. Would need to use tcpdump or wireshark to see what's being sent, probably boot the Synology and see what the source IP address is on the packets that it spits out. If it's trying to use a static IP address, can just configure your router to reserve that static IP for the thing, or maybe change the reserved address range it uses to be one that includes the Synology device if it isn't.

    I...may be out of date here, but I don't know if you can connect your desktop and your Synology device directly, unless the Synology device has some special mode. Traditionally, you need a special cable, an Ethernet crossover cable, to do this. reads article. WP says that "many devices" can handle running without a crossover cable these days. shrugs

    If not, you can make it work if you have a hub (well, switch) lying around. Plug the desktop and the Synology device into the thing. That'll let you see any traffic the NAS tries sending, not just broadcast traffic.

    • I really appreciate the detailed response! Thank you very much

      Turns out plugging the Ethernet in does actually work. I was able to access the server from my computer using the same IP address as it originally had

      From there I just had to turn "Use DCHP" back on to get a new IP from the router