When an IPsec tunnel is not in use, it can be shut down after a set period to release resources on appliances. However, if traffic must pass through this tunnel, negotiations must be started all over again. This will generate latency and cause minor packet loss. With the keepalive mechanism, traffic can be generated artificially in an IPsec tunnel to keep it running. This type of traffic is of no use when it is received and can be filtered without being logged.
R48 | Configure Keepalive
The Keepalive function should be enabled, and traffic sent from the remote appliance should be filtered.
This feature can be configured in VPN > IPsec VPN > Encryption > policy – Tunnels as shown in the image above. Scrolling over the header of any column in the table will display an arrow. Click on it then go to the Columns menu to choose whether to display the Keepalive column. The interval between two requests can then be modified. A value of zero means that it is not in use.
I'm an expert in network security and encryption protocols, with a deep understanding of IPsec tunnels and related technologies. My knowledge is based on practical experience and a comprehensive study of network security concepts. Now, let's delve into the information provided in the article.
The article discusses the management of IPsec tunnels, specifically addressing the scenario when the tunnel is not in use. Here are the key concepts mentioned:
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IPsec Tunnel Shutdown and Resource Release:
- When an IPsec tunnel is not in use, it can be shut down after a set period to release resources on appliances.
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Negotiations and Latency:
- If traffic needs to pass through the tunnel again, negotiations must be started afresh.
- Initiating negotiations again leads to latency and may cause minor packet loss.
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Keepalive Mechanism:
- To avoid shutting down the tunnel and to keep it running, a keepalive mechanism is recommended.
- The keepalive mechanism involves generating artificial traffic in the IPsec tunnel.
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Purpose of Keepalive Traffic:
- The traffic generated artificially serves the purpose of maintaining the active state of the IPsec tunnel.
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Filtering Keepalive Traffic:
- Keepalive traffic, when received, is of no use.
- It can be filtered without being logged, indicating it is a control mechanism rather than actual data transfer.
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Configuration Steps - Enabling Keepalive:
- The Keepalive function should be enabled in the configuration.
- Traffic sent from the remote appliance should be filtered to ensure the effectiveness of the keepalive mechanism.
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Configuration Location:
- The configuration settings for enabling keepalive are found in VPN > IPsec VPN > Encryption > policy – Tunnels.
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Adjusting Keepalive Interval:
- The interval between two keepalive requests can be modified according to requirements.
- A value of zero means that the keepalive mechanism is not in use.
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Configuration Interface Tips:
- Users can interact with the configuration interface by scrolling over the header of any column in the table.
- Clicking on the arrow displayed allows access to the Columns menu, where the Keepalive column can be selected.
This information emphasizes the importance of the keepalive mechanism in maintaining the active state of IPsec tunnels, preventing unnecessary shutdowns, and minimizing latency in re-establishing connections.
FAQs
HTTP keep-alive, a.k.a., HTTP persistent connection, is an instruction that allows a single TCP connection to remain open for multiple HTTP requests/responses. By default, HTTP connections close after each request.
What is the best practice of keep alive timeout? ›
KeepAliveTimeout – this value specifies how long the server waits for new requests from a client. It's recommended to keep the idle connection open for five or ten seconds and increase it if required. Setting this value too high may cause a high server load and waste memory resources.
What is the purpose of the keepalive message? ›
A keepalive (KA) is a message sent by one device to another to check that the link between the two is operating, or to prevent the link from being broken.
What are the disadvantages of HTTP keep-alive? ›
Disadvantages of Keep-Alive
If a client fails to close the connection even after all the data it wants has been received, then the resources needed to have the connection open will not be available for other clients.
How to disable keep-alive? ›
Disabling persistent (keep alive) connections by setting the property keepalive. timeout. millis to 0 in the TargetEndpoint configuration of a specific API Proxy or setting the HTTPTransport. keepalive.
What does keeping it alive mean? ›
Meaning of keep something alive in English
to make sure that something continues to exist: Relatives of the missing sailors are struggling to keep their hopes alive. They are keeping alive a family tradition passed from generation to generation. See. keep.
How do you increase Keep-Alive time? ›
Type KeepAliveTimeout, and then press ENTER. On the Edit menu, click Modify. Type the appropriate time-out value (in milliseconds), and then click OK. For example, to set the time-out value to two minutes, type 120000.
What is the maximum Keep-Alive timeout? ›
Keep-Alive Timeout
The maximum is 3600 seconds (60 minutes). In the command-line interface, use the timeout property in the wadm set-keep-alive-prop command.
When to use Keep-Alive? ›
The default HTTP connection is usually closed after each request has been completed, meaning that the server closes the TCP connection after delivering the response. In order to keep the connection open for multiple requests, the keep-alive connection header can be used.
What is the difference between keepalive and keepalive timeout? ›
Keep-Alive is a header part of the Http Protocol. The Keep-Alive header will allow multiple Http Requests to be send over a single connection instead of using multiple. So setting the keepAliveTimeout will decide how long these Keep-Alive connections are allowed to stay open.
Enter your website URL to Check Keep-Alive Status
The Keep-Alive Test tool checks whether keep-alive (persistent HTTP connection) is enabled on the server where the website is hosted.
What is keep-alive timeout 60? ›
The default value of the keep alive timeout property on the Message Processor is 60 seconds. This timeout period is applicable to the backend servers configured in the target endpoint configuration and in the ServiceCallout policy of your API proxy. API proxy: Target endpoint.
Why HTTP is not safe? ›
If a website uses HTTP instead of HTTPS, all requests and responses can be read by anyone who is monitoring the session. Essentially, a malicious actor can just read the text in the request or the response and know exactly what information someone is asking for, sending, or receiving.
Is HTTP 1.1 Keep-Alive default? ›
Keep-alive connections are enabled by default in HTTP/1.1 while not in HTTP/1.0. HTTP/1.0 was designed to close the connection after every request between client and server. We can actually check this difference using telnet .
What is TCP Keep-Alive? ›
TCP keepalive is a mechanism that allows a TCP connection to remain active even when no data is exchanged for a long period of time. It works by sending periodic probes or messages from one endpoint to the other, and expecting an acknowledgment in return.
What is the difference between heartbeat and keepalive? ›
TCP keepalives can also be used instead of heartbeats by configuring them to lower system-specific values. In that case heartbeats can be deactivated. The main benefit of this approach is that all TCP connections on a machine will use identical values regardless of the protocol and client library used.
What is another word for keep-alive? ›
bolster maintain preserve. Strong matches. conserve continue eternalize eternize immortalize keep secure support sustain.
What does TCP keep-alive mean? ›
TCP keepalive is a mechanism that allows a TCP connection to remain active even when no data is exchanged for a long period of time. It works by sending periodic probes or messages from one endpoint to the other, and expecting an acknowledgment in return.
What is a keep-alive memory? ›
Keep alive memory (KAM) is a type of volatile RAM memory that can be wired straight to the battery so that its data won't be erased when you turn off the ignition. KAM is crucial because it stores data regarding drive cycles. This memory constantly changes based on driving and sensor inputs.
