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astra4

join:2004-08-17

How Lookup MAC Address of Device connected to ZyWall USG 100

I have a problem with a device connected to a LAN port of my ZyWall USG 100.

The device is a NAS and the problem is it doesn't request an IP from the DHCP service anymore, and because it has no IP I can't access it anymore.

Apparently there's a chance to regain access by configuring the router with a fixed IP assigned to the MAC address of the device connected to it, and that's what I want to try.

For that I need to know this MAC address.

I tried the command "show mac" in ZyWall Console, but that would show the ZyWall's own MAC address range and not the MAC addresses of connected devices...

Anyone have an idea how to use the show command to display the MAC addresses of connected devices?

Or any other approach to this end?



Hank
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2 edits

When you log into the USG-100 the Dashboard should appear. In the upper left hand side you should see the DHCP table listed. Click on it and it will provide you with the information you need. Also when you have that table open you can reserve the IP address assigned to the device. Unless you powering the NAS or our router up and down the IP address should not change. Hope that helps.

You should also be able to set your NAS up to use a fixed IP. Set it up to use the IP your reserved in the DHCP table. Then again it should not make any difference because once reserved in the routers DHCP table that is the only IP address that will be assigned to that MAC address.


astra4

join:2004-08-17

Thanks for the reply.

The NAS doesn't show up in the DHCP table, even though it's (supposedly) configured to use DHCP and the status of the corresponding ZyWall LAN port is UP. Apparently the NAS doesn't request an IP as it is supposed to...

Maybe what I had in mind is not possible. Apparently CISCO routers know the command "show mac address-table" but, possibly, this will only show the MAC addresses of devices which are "logically" connected to the router, in the sense that they have been assigned an IP.

Anyway, I meanwhile managed to find the box (original packaging) of my NAS, on which the MAC address is written.

Now I just need to figure out how to assign a fixed IP to this MAC address in my ZyWall...



Hank
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Pick an IP address in the range of the DHCP, then go in and setup your NAS to use that address. Are you sure that you don't have a bad cable going to the NAS or try a different port on your router or switch. Also try powering the NAS down and see if it pulls an IP address.



Hank
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I was going to list a different route but not sure it will work. Also if you cannot get into the NAS you would not be able to setup the fixed IP. I wasn't thinking very well here. But you probably did try power down and restarting you NAS ro see if it would pull an IP.



Hank
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1 edit

Try "show ip dhcp ip pool"

You have the MAC address so you should be able to find it if the NAS is pulling an IP.

You didn't by chance have the NAS setup to use a fixed IP before?

Also you can get the CLI commands from the ZyXel web site. It may be helpful to you.


OZO
Premium
join:2003-01-17
kudos:2
reply to astra4

Try tools like this - SoftPerfect Network Scanner
--
Keep it simple, it'll become complex by itself...


astra4

join:2004-08-17

@Hank
- it's not pulling an IP, if it did I'd see that in dashboard. I have an experimental setup with just a couple of devices, hence no problem to find an IP, if it's there at all.

- yes the NAS was configured with a fixed IP. But then it disappeared from the network. And finally I pressed its reset button, to reset its network config to default, which is DHCP.

@Ozo
-thanks for the scanner tip. Had similar idea myself, tried WireShark Network Analyzer, amazing how much activity there is on a virtually inactive network, anyway I couldn't make any sense of all the captured activity.

- one thing I noted is in ZyWall Port Statistics, I get some TX but zero bytes RX activity on the port to which the NAS is connected.

Anyway, I'll send a support request to the manufacturer of the NAS and hope they have a solution.



Brano
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1) If you have physical access to the NAS server, MAC address should be on the sticker.
2) If the NAS is communicating through USG (and the NAS's IP is working but unknown) then you can look it up by show arp-table
3) Connecting the NAS via direct cable to a PC/Laptop with wireshark should let you figure out the MAC address quite easily. (Actually, packet capture on USG on the right interface should do the same trick.)
4) Then there's always reset to defaults button somewhere on the NAS. Check the manual, on most devices there's config reset and data are preserved (make sure you check the manual first and/or pull the disks first).