Thin Clients(aDesk-STD220) Unable to Obtain DHCP IP Address While PCs Work on Same Port (Sangfor VDI Environment)

Michael Addisu Lv1Posted Apr-04-2026 22:27

I am experiencing an issue where thin clients are unable to obtain an IP address via DHCP, while a PC connected to the same switch port successfully receives an IP address without any issues.
Details:

  • DHCP server is functioning correctly (confirmed with PC test)

  • Same network port and cable used for both PC and thin client

  • Issue is consistent across multiple thin clients

  • Thin clients fail to obtain IP address

Troubleshooting Done:

  • Verified DHCP server functionality

  • Tested same port with PC

  • Checked physical connectivity

  • Restarted thin clients



  • Are there specific network configuration requirements for Sangfor thin clients to obtain DHCP leases?

  Any recommended steps to diagnose or resolve this issue at scale (205 devices)?

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Yes, Sangfor thin clients aDesk-STD220 may fail to get DHCP IP even when PC works on same port due to network configuration differences.
Check these points:
Switch Port VLAN
Port should be in Access mode
Correct VLAN assigned
DHCP Scope
Ensure enough free IP addresses
Gateway (Option 3) and DNS (Option 6) configured
Port Security / NAC
Disable MAC binding, 802.1X, sticky MAC if enabled
DHCP Relay
If DHCP server is in another VLAN, configure ip helper-address
Firmware
Update aDesk-STD220 firmware from Sangfor console
Enable PortFast
Prevent DHCP delay issue
Recommended at scale (205 devices):
Test 1 device → verify VLAN & DHCP → apply same switch configuration to all ports.
Most cases issue is VLAN mismatch or port security restriction.


Is this answer helpful?
Prosi Lv3Posted Apr-07-2026 11:33
  
Yes the thin clients require:
•        DHCP: PXE-related
•        Correct VLAN + relay handling
•        No blocking of DHCP broadcast (ports 67/68)
•        DHCP mode enabled on device
Muhammad Abid Lv2Posted Apr-07-2026 12:12
  
Yes, Sangfor thin clients aDesk-STD220 may fail to get DHCP IP even when PC works on same port due to network configuration differences.
Check these points:
Switch Port VLAN
Port should be in Access mode
Correct VLAN assigned
DHCP Scope
Ensure enough free IP addresses
Gateway (Option 3) and DNS (Option 6) configured
Port Security / NAC
Disable MAC binding, 802.1X, sticky MAC if enabled
DHCP Relay
If DHCP server is in another VLAN, configure ip helper-address
Firmware
Update aDesk-STD220 firmware from Sangfor console
Enable PortFast
Prevent DHCP delay issue
Recommended at scale (205 devices):
Test 1 device → verify VLAN & DHCP → apply same switch configuration to all ports.
Most cases issue is VLAN mismatch or port security restriction.


Zonger Lv5Posted Apr-08-2026 00:35
  
Sangfor thin clients do not require any special DHCP configuration beyond standard IPv4 DHCP so if PCs work on the same port but multiple thin clients fail the issue is typically related to network access control or DHCP filtering rather than the clients themselves.  At scale (205 devices) first verify whether port security, MAC binding or 802.1X/NAC policies are restricting unknown MAC addresses as thin clients often use different OUIs. Then check if DHCP snooping or VLAN assignment is blocking requests ensure the correct VLAN/tagging is applied on the switch port and confirm the DHCP scope has sufficient leases for diagnosis, capture traffic (SPAN/Wireshark) to see if DHCP Discover packets are sent/received. Review switch logs for dropped requests and test by placing a thin client on an open/unrestricted port. If it works, replicate that configuration across all access ports or whitelist the thin client MAC ranges.
Simone Eusebi Lv1Posted Apr-10-2026 15:08
  
Can you explain better which DHCP are you using? The DHCP role is offered by a switch, a router, a firewall, a vm (Linux? Windows?), which daemon is doing it (release?)

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