Symptom: The Vpn Tunnel Works But Needs To Be Faster - SonicWALL TZ 180 Recommends Manual

Troubleshooting TZ 180 Configuration and Settings Issues
Click on the Apply button in the upper-right-hand corner, then click on the Close button in the
lower-left-hand corner to return to the management interface. Restart the SonicWALL for the changes to
take effect. With these settings disabled, the SonicWALL performs cryptography in software, which reduces
VPN throughput but is still functional.
If disabling hardware cryptographic fixes the problem, contact SonicWALL technical support
Note
to arrange for further diagnostics.

Symptom: The VPN Tunnel Works but Needs to be Faster

A VPN tunnel is limited by the slowest point between the two links. This is often referred to as the
chokepoint. For example, if you have a VPN tunnel between a central office that has a 1.5Mbps T1
connection to the Internet and a remote office that has a 256Kbps ADSL connection to the Internet, the
VPN tunnel is going to be constrained by the ADSL connection speed and also by any traffic flowing in and
out of that connection at any time (for example, if there is someone at the remote office downloading data
in high volumes from the Internet, the VPN tunnel is likely to be even slower). Distance may also affect
perceived throughput. The farther apart the two links, the slower it may seem, due to a number of factors,
including latency, potential for packet loss and retransmission, or transient traffic in between the two points.
There are settings on the SonicWALL security appliance that may improve throughput.
Log into the SonicWALL security appliance management interface. Navigate to the VPN > Advanced page
and check the boxes next to Enable Fragmented Packet Handling and Ignore DF (Don't Fragment)
Bit. Click on the Apply button in the upper-right-hand corner then reboot the appliance for the changes to
take effect.
For further assistance, refer to the Site-to-site VPN Troubleshooting on SonicWALL Security Appliances technote,
available at:
http://www.sonicwall.com/downloads/site_to_site_vpn_troubleshooting_on_sonicwall_security_applian
ces.pdf
24 SonicWALL TZ 180 Recommends Guide