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Zero Client Troubleshooting
Zero Clients that are not playing content are in one of the following states and show messages for each state. Here is what you can do with each.
The Zero Client is currently trying to acquire a DHCP IP address. Generally, this should only show for 10-30 seconds, at which point it will change to Not Assigned to a Host PC...
If the message persists for longer than 30 seconds, it is either because the Zero Client has no network connection or the Zero Client has not received a DHCP lease from the network. In either case, eventually, the Zero Client will give itself a local IP such as
10.10.254.10and periodically check for new DHCP leases.
This message is shown when the Zero Client has an active network connection and an IP address but is not currently assigned to a Userful server. Either it is a new out-of-box device, or it has been purposely un-assigned from a Server.
This message is shown when the Zero Client has an active network connection, and an IP address, and has been assigned to a Userful server, but is not intentionally un-assigned from that server.
The Server is either offline or rebooting. Check the server to make sure it is up and running. Rebooting can sometimes clear up issues with the Zero Client driver, though these are rare.
This message is shown when the Zero Client is in the process of connecting to the server. It disappears after a few minutes.
Zero Clients that are on the same physical subnet as the Userful server will always show up in the Control Center - even if they are set with an invalid IP address and/or subnet mask. If they do not, check the following points:
- Ensure that the server and client are on the same network - this could be an L2 (physical) or L3 (virtual) network routing issue. This is very common after a server and zero clients are moved networks. This is the most common cause of displays not showing up in the Control Center. Zero Clients are not cross-subnet compatible, but uClients are, as long as Internet connectivity is present.
- Ensure Zero Clients and all related network equipment are powered on.
- Ensure all network connections are physically present and in good repair.
Zero Clients can be completely isolated from the Internet, uClients require access.
Userful servers typically ship with and make use of two network adapters - one to connect to the primary corporate network and one to exclusively feed clients. However, a client device will connect over either adapter so long as it is powered and physically connected to the same network.
If a Zero Client will not complete the process of assigning itself to your server but instead continues to be in a "Connecting..." state, there are two things to check.
First, ensure the network adapter settings match the subnet of the Zero Clients.
If the Zero Clients are on a different subnet than the server, they may not have proper DHCP leases and need to be power cycled, or another configuration change may be necessary.
Second, the Zero Client may be experiencing an IP conflict with one or more devices - either another Zero Client or another network device.
If the Zero Client is powered off but your pings return as pictured above, then there is another device occupying that IP address that must be dealt with.
Userful will show a warning message if any zero clients are not running at 1Gb/s (1000Mb/s) speeds. If the Zero Client is connected to a 1Gb/s link, resetting the Zero Client with the power switch (turn it off for 30 seconds) can clear this problem up.
- 1.Click on the RESET button next to the Kensington lock. While holding the RESET button:
- Power off the device after 15 seconds.
- Wait for 15 seconds and power on the device.
- 2.Hold the RESET button for 15 more seconds and the device will completely reset.
- 1.Click on the Reset button present in the small hole between the power switch and the VGA output.
- 2.With the device powered on, press and hold the RESET button for 15 seconds. The Zero Client will return to factory settings within 30 seconds.
- 1.Power off the device and disconnect the network cable.
- 2.Connect four USB flash drives to each USB port on the device, disconnecting any USB peripherals such as keyboard or mouse and replacing them with flash drives. The contents of the drive are irrelevant, Userful cannot read them while disconnected from the network.
- 3.Power the device on. In 10 seconds, the blue LED light begins flashing.
- 4.Disconnect all 4 USB flash drives within 10 seconds.
- 5.Wait for the LED to stop flashing and become solid blue.
- 6.Power the device off and switch it On again. It is now reset to factory settings.
One or more network zero client(s) freezes or drops its session, seemingly without cause.
- IP conflict to the relevant host or zero client(s)
- DHCP changes or Address space exhaustion
- Damaged or loose network cabling or other infrastructure
- Outdated software. Check for system updates
- Excessive traffic on the subnet
- Inadequate networking hardware
- QoS or packet shaping rules are in place
- Subnet shared with an open-access device such as public WiFi
- Host PCs and zero clients should always be set to static IPs where possible.
- Where possible, separate as much staff/wireless traffic from the system as possible.
- Network hardware should be inspected and repaired where necessary.
- Check all link speed lights on their network gear to ensure proper 1Gbps connectivity. This includes ports connecting the hosts, zero clients, and any ports that bridge switches, which may not be directly detected by UCC.
- All cabling should be at minimum Category-5. 5e is of course the published minimum spec, but 5 will work as long as everything is in good condition.
- Ensure all zero clients have updated firmware.
- Check the network for latency and/or packet loss issues
DHCP is the most important thing to check first, for a number of reasons. If a zero client's IP address changes, it must drop and re-associate with the host, causing the station to reset. This happens more often than you would think - yes, most of the time a client will get the same IP back. However, some locations do not, and Address space exhaustion is very common in environments with public WiFi access. Zero clients that have to share a subnet with such things are not going to be stable.
In the most sensitive cases, a complete, protected subnet or VLAN should be created for the Userful system in its entirety. A customer or patron should not be able to walk into the establishment, fire up their tablet or laptop, and affect or communicate with a zero client or Userful host in any way, through either wired or wireless interfaces.
Not all gigabit switches are created equal. A $49 off-the-shelf device from Staples or Wal-Mart cannot handle the traffic requirements of zero clients. As a general rule, any switch used should be rack-mountable and cost somewhere north of $100 at minimum. Known-good, inexpensive, and readily available models include the Cisco SG110D and Netgear Prosafe GS series. Higher-end managed switches are generally fine.
This occurs when brand-new zero clients are installed on a network with no DHCP. They will look for DHCP for about 30 seconds, then revert to 169.254.10.10 and appear in a different subnet in UCC.
Unplug the power from the Zero Client for at least 60 seconds and plug it back in. If successful, the Zero Clients will be able to be assigned to the host on the Displays screen within the Userful Control Center.
This may take 2-3 attempts. If the issue persists, contact Userful Support.
- Ensure all USB connections are firmly in and undamaged.
- Ensure that the zero client is not connected to any USB 3.0 ports. They will either be colored blue or have an "SS" logo next to them.
- Check the power supply and condition of the surge protectors. Also, ensure that the UPS is in good condition and not more than three years old.
This problem usually happens when Secure Boot is enabled in the BIOS. You will need to go into the BIOS and disable this (usually in Advanced Settings on the majority of BIOS interfaces).