GVC: Semaphore Timeout Period Expired on Global VPN Client (GVC) Virtual Adapter

03/26/2020 10 13081

DESCRIPTION:
GVC: Semaphore Timeout Period Expired on Global VPN Client (GVC) Virtual Adapter

RESOLUTION:

Problem Definition:

Problem Symptom: When remote users connect to SonicWall WAN GroupVPN using GVC they may get the error: "Failed to renew the IP address for the virtual interface. The semaphore timeout period has expired". This error occurs after Phase I and user authentication has been completed.  

Resolution or Workaround:

Solution: This happens when the virtual adapter of the Global VPN client does not receive an IP lease from the DHCP server of the SonicWall or the DHCP server behind the SonicWall. 

Workaround: Upgrading the client is the recommended route for this type of error. However, if you encounter difficulties with the installation, are unable to perform the upgrade for some reason, or the upgrade did not resolve the issue, there are several workarounds that have been successful. These workarounds are meant to be tried one at a time, and not all at once.

• If DHCP Lease has been selected under WAN GroupVPN > Client > Virtual Adapter Settings, ensure DHCP over VPN has been configured to use either the internal SonicWall DHCP server for Global VPN Clients or a network DHCP Server.
• If using a network DHCP Server, disable it and try with the SonicWall DHCP Server.
• Turn off NAT Traversal if the upstream device is doing a NAT traversal, under VPN > Advanced. Note: This is a global settings and will affect other VPN tunnels.
• Turn off Apply NAT and Firewall Rules in SonicOS Standard:
  • Click VPN-> Settings. Under VPN Policies select GroupVPN.
  • Click on the Advanced tab and uncheck “Apply NAT and firewall rules”. Click OK to apply the settings.

• In the SonicWall Group VPN change the encryption settings on both phases to DES and MD5.
  • Firmware 6.x: Click VPN > Configure > Group VPN. Under Security Policy, Phase 1 should be DES and MD5 and Phase 2 should be Encrypt (ESP DES).
  • SonicOS Standard: Click VPN > Configure > Group VPN > Proposals. Set Phase 1 to DES and MD5 and Phase 2 to ESP and DES.
  • SonicOS Enhanced: Click VPN > Configure. Choose the Group VPN policy experiencing the issue. Select the Proposals tab. Set Phase 1 to DES and MD5 and Phase 2 to ESP and DES.

• Disable the DHCP server on the SonicWall, restart the SonicWall and enable the DHCP server again.
  • Firmware 6.x: Click DHCP > Setup. Check “Disable DHCP server”. Restart the SonicWall and check “Enable DHCP server”.
  • SonicOS Enhanced or Standard: Click Network > DHCP Server. Uncheck “Enable DHCP server”. Restart the SonicWall and check the same box again.

• Enable fragmented packet handling on the WAN interface and reduce the WAN MTU.
  • Firmware 6.x: Click the Advanced > Ethernet tab. Under MTU settings, check “Fragment outbound packet larger than WAN MTU”. Also change WAN MTU to 1404.
  • SonicOS Standard: Click Network > Settings > Configure for the WAN interface - Ethernet tab. Check “Fragment Non-VPN outbound packets larger than WAN MTU”. Also change the MTU setting to 1404 on this page.
  • SonicOS Enhanced: Click Network > Interfaces > Configure for the WAN interface - Advanced tab. Check “Fragment Non-VPN outbound packets larger than WAN MTU”. Also change the MTU setting to 1404 on this page.
• In the SonicWall, try turning off all DHCP-over-VPN related settings entirely. (In some scenarios, a virtual IP address is not even needed for basic VPN connectivity and functionality). If DHCP-over-VPN settings are already off, then enable them and try to connect to the VPN.
  • Firmware 6.x: Choose the VPN > Configure tab and select Group VPN > Client Settings. Under Client Connections, uncheck “Use DHCP to obtain virtual IP for this connection”. Click OK.
  • SonicOS Enhanced or Standard: Click VPN > Settings > Group VPN > Client tab. Under Client Connections, set Virtual Adapter Settings as None. Click OK.

If the above steps do not resolve the issue, uninstall the Global VPN client, run the VPN cleanup tool and try reinstalling the Global VPN client.

On the Global VPN client:

1. Right click on the connection that you have created and click Properties.
2. Click Peers > Edit.
3. Under “Advanced Packet Transmission Settings”, set both the Response Timeout and Send Attempts to 10.
4. Click DPD settings.
5. Under “Specify conditions under which DPD packets are sent”, choose “Whether or not traffic is received from the peer.”
6. Reconnect.
7. On the client machine, which has GVC, check if there is any software firewalls or AV packages installed. If there are any, uninstall them and then try to connect.

You can also try the following from the GVC:

1. Right click on the SA that you have created and click Properties.
2. Click Peers > Edit > Interface selection and choose LAN only.
3. You can also turn off NAT traversal if the upstream device is doing a NAT traversal.

It will be necessary to check your upstream device (Router, Managed switch, Cable or DSL modem, etc) for instances of IPSec NAT traversal being enabled. If found, disable that option. Also on the upstream device, UDP 500, UDP 4500 and IP protocol 50 should be open. This may be known as IPSec pass through on some routers.