The RSYNC error “Unable to resolve hostname” usually arises when RSYNC cannot translate the hostname into an IP address. This translates into a problem with your Domain Name System (DNS) lookup or network connectivity. To resolve this issue, consider the following steps:
1. Check Hostname Resolution: Test if your system can resolve the hostname to an IP address successfully. For this, you can use the `ping` or the `nslookup` command.
\`\`\`bash ping your\_hostname \`\`\`
or\`\`\`bash nslookup your\_hostname \`\`\`
If these commands fail to resolve the hostname, then there’s an issue with the DNS configuration on your system which needs to be addressed.
1. Check DNS Configuration: If you’re using Linux, open the `/etc/resolv.conf` file and check the DNS server’s settings. If the settings are incorrect or the DNS server is not working, you need to correct the settings or contact your network administrator.
\`\`\`bash nano /etc/resolv.conf \`\`\`
After checking and correcting, retry the ping or nslookup command to see if it’s resolved.
1. Check Network Connectivity: Ensure that your system can communicate with the network where the host resides. Use `ping` command to test your network connectivity.
1. Check Rsync Command: If all the above are working fine, the error can also be due to the incorrect use of the rsync command. A typical rsync command to copy files from one server to another looks like:
\`\`\`bash rsync -avz /path/to/source_files username@your_hostname:/path/to/destination \`\`\`
Ensure that you replace `/path/to/source_files`, `username`, `your_hostname`, and `/path/to/destination` with actual source files’ path, username, hostname, and destination path respectively.
If you have correctly implemented all the steps and the problem persists, there may be more specific network issues, or server-side problems that require the attention of your network administrative team.
As reference to construct this answer, several well-known Linux documentation and forums were used, including the `man` pages (manual pages in Linux for command-line utilities), various articles on sites like StackOverflow, Linux Handbook, and Tecmint.
Please consult with your system administrator for the best security practices and remember to execute commands according to your user rights and security policies.
