A Linux endpoint is not reporting as registering to the Cloud though the MCS.log file and config file show that it has registered. The following error may be seen if the Linux machine is not registered in the DNS A records or hosts file so the lookup against itself fails:
subprocess.CalledProcessError: Command '['hostname', '-f']' returned non-zero exit status 1
This will probably be due to a name resolution issue when the Endpoint is trying to register itself to Cloud. During this process two DNS queries are performed from the EP, one to the AWS cloud server,the other is to the Linux machine itself
The lookup process is as follows:
- DNS lookup from EP for AWS cloud
- Once IP address is identified by DNS lookup, TLSv1 session to AWS cloud is made. (typically ‘Server Hello’ is communicated.)
- DNS lookup for the Linux machine itself.
- Once the lookup for itself is successful, the next TLSv1 session with AWS cloud is made. (typically ‘Client Hello’ is communicated.)
When this error is seen the Linux machine is not registered in the DNS A records or hosts file so the lookup against itself fails.
The following sections are covered:
Applies to the following Sophos products and versions
Sophos Anti-Virus for Linux
Once a record in the DNS server for the Linux machine has been specified the registration with Sophos Central should proceed. Alternatively, the hosts file can be updated by adding the machine name of the Linux machine itself.
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