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TR7Enterprise Application Delivery & Security Platform
What does the configuration error(s) warning in the vService preview (DNS Resolution Error, Port binding error) mean; where does Port Collision appear?
Short answer
The N configuration error(s) line in the Details tab of the vService preview is a summary, divided into categories, of the errors that occur while the vService's configuration is loaded; N is the number of categories, not the number of error lines. DNS resolution error shows that the domain name of a Backend Service could not be resolved, and Port binding error shows that the frontend IP and port could not be opened for listening; the other categories are errors such as syntax, unknown reference, certificate file and cipher list. Port collision, on the other hand, appears in the vService form, not in the preview; it says that a frontend was entered that collides with a port used on the same IP by another vService, Management Access or GTM, and the record cannot be saved.
Categories in the Preview
| Category | Meaning | What is done |
|---|---|---|
DNS resolution error | The domain name written in the Backend Service address could not be resolved | The Device DNS setting and the name are checked (with sys-cmd dig in WEB-CLI), or the address is changed to an IP; then the vService is reloaded |
Port binding error | The frontend IP and port could not be opened for listening | It is checked on the Network → Interfaces screen that the IP is active on the interface, and that the port is not used by another service on the device; if necessary, the IP or the port is changed |
SSL certificate file error | The certificate or CA file could not be opened | The certificate is uploaded again or its selection is corrected (What does the vService do if the certificate I uploaded has an error?) |
SSL cipher list error | The cipher list could not be applied | The cipher list in the SSL Security profile assigned to the vService is corrected |
Configuration syntax error · Parse error · Configuration load error | The configuration could not be parsed or loaded | The last change is undone; if the problem persists, a support bundle is taken |
Unknown reference | The configuration refers to a server or group that does not exist | The related Backend Service or routing rule is checked |
Script error · Permission error · Unsupported feature · Resource allocation error | Other loading errors | The line is forwarded to the support team (Which information should I collect before contacting TR7 support?) |
Definitive rules:
- The line is collected from the loading errors at the moment the vService is created, edited or restarted; it appears only in HTTP and L7 TCP vServices. In a cluster, it is shown separately for each device.
- An error line can fall into more than one category; for example, a server name that cannot be resolved can appear together with
Parse error. - If the configuration cannot be loaded, the vService status can be Error; at this moment an encrypted diagnostic bundle is also produced (How do I download the encrypted diagnostic bundle for the support team (Encrypted Support Bundle)?).
- The domain name in the Backend Service address is resolved while the configuration is loaded; after the DNS record is corrected, the vService is reloaded (Can I enter a domain name (FQDN) instead of an IP as the Backend Service address?).
Where Is It Monitored?
| Screen | Path | What it shows |
|---|---|---|
| Details | Load Balancer vServices → vService → right panel | The N configuration error(s) line and its categories; per device in a cluster |
| Status Logs | In the same panel | The status transitions caused by the error and, if any, the Encrypted Support Bundle |
| vService form | Load Balancer vService List → Edit → frontend row | The Port collision validation error |
Port Collision
The Port collision: X & Y error appears in the frontend table of the vService form, and the record cannot be saved. The entered IP and port collide with one of the following:
- Another frontend row in the same form,
- The frontend of another vService (except those in the same Virtual Hosting group),
- The Management Access ports (HTTP, HTTPS, SSH, SNMP, FTP),
- The GTM DNS service listeners,
- The UDP use on the same port by an HTTPS frontend with HTTP/3 on.
For more than one vService to share the same IP and port: Can I define more than one vService on the same IP:port?
Common Misconceptions
- "N is the number of error lines." N is the number of different categories; a category can contain more than one line.
- "Port collision appears in the preview." Port collision appears only in the form and prevents the record from being saved.
- "Correcting the DNS record is enough." The name is resolved while the configuration is loaded; after the correction, the vService is reloaded.
- "This line also appears in a Network vService." The line is collected only in HTTP and L7 TCP vServices.
How it is done in the documentation
