Virtual Private Networks (VPNs) allow secure connections through the open internet. With VPN authentication, encryption, availability, and speed, end-users can work from anywhere as if they were sitting within a millisecond’s ping from the server room. Remote branch offices are connected, cloud resources are securely available, and all is well. That is, if the VPN tunnel works as it should.
Colleagues not talking to each other? Could be a grudge, could be trouble joining the call because “that VPN tunneling thingy keeps timing out.” No traffic from the remote office? Could be just lunch break, could be that the site-to-site VPN tunnel is down. What if it really is the network this time?
Setting up a trusted tunnel between two endpoints is a multi-step process—this also means that troubleshooting requires knowledge of its complexity. See these handy VPN tunnel troubleshooting flowcharts for LAN-to-LAN and Remote Access VPNs for examples of a systematic approach to figuring out why the remote connection is flunking out.
In short, you need to:
Send packets that are recognized as initiating a VPN connection attempt.
“Phase 1” establishes a secure communication channel by generating a shared secret key to encrypt further communications. Troubleshooting this phase often deals with IP addressing, encryption config, or pre-shared keys.
Following the working secure channel, in “Phase 2,” you establish IPSec security associations and negotiate information needed for the IPSec tunnel—connection type, authentication method, and access lists—resulting in a crypto map.
On we go to the data transfer: encrypted, authenticated, and secure.
When the VPN connection fails and it’s troubleshooting time, you want visibility into your VPN environment. We’ve come up with Network Insight™ for Cisco® ASA to help you with just that. One of the most popular security devices on the market meets the worldwide leader in network management software. Sounds promising, right?
In SolarWinds® Network Performance Monitor 12.2, your monitored ASA devices now show additional information beyond SMNP statistics.
Site-to-Site VPN shows you whether the tunnel is up, down, or inactive. See traffic ingress and egress, duration of the VPN tunnel uptime, encryption, and hashing info. If the tunnel is down, information about the last phase completed successfully is available. Search, filter, and favorite tunnels to quickly access them in the Node Details view. You can also select specific errors from Phase 1 or Phase 2 to be ignored.
The Remote Access VPN subview presents a list of remote access tunnels, with the username and tunnel duration details, as well as the amount of data downloaded and uploaded. For failed connections, you’ll see the time and reason why the connection was ended, IP address, and client used. As always, you can use tools to search and filter the sessions.
Several predefined reports and alerts are available to keep your finger on the VPN’s pulse. Tunnel down? You’ll know first. Reaching a threshold? Won’t catch you by surprise. And of course, you can customize your own advanced reports and alerts.
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