The syslog syntax in VyOS 1.3.x and earlier didn't have an explicit port option and also had no restrictions on the host node syntax.

In 1.4.0, we introduced a new port option and restricted the remote node to IP addresses and FQDNs.

However, due to the lack of an explicit port option, people were including ports in node names — that used to work with the old config script.

system {
 syslog {
     host 192.0.1.1:9000 {
         facility all {
             level "info"
         }
     }
   }

We need to account for the existence of such configurations and migrate the port part to the new port option.

Unfortunately, a straightforward fix will lead to configuration data loss when someone was using the node name syntax loophole to send different log messages to different ports of the same server. Such configurations are currently unsupported. If we agree upon the approach for making them valid again (T8058), we can adjust migration scripts to account for that.