Hi guys, long time lurker, first time poster!

We utilise Miktrotiks (RB951Ui -2HnD) for captive portal hotspots and after receiving a "fresh batch" of Mikrotiks our config system no longer works, after putting the config on the box when the box reboots it comes back up in an "broken" state, ( i am unable to establish a connection back to the box - pings fail) i am currently unable to find out what the problem is (lack of knowledge on mikrotik logging) with these fresh boxes.

The only difference we can currently see is that every existing box we have had (100+) - the serial numbers have all began with 628305 whereas our new boxes start with 4AC7041 or 558304.

i was wondering if their is any significance with this at all or a point in the direction of what i should be looking for would be great.

Kind regards, Mal

Be aware that RouterOS is a quiet picky when it comes to config files with respect to versions.
Some commands do not exist anymore in newer versions.
So make sure your config file is compatible with the designated RouterOS version.

Do you put only a config on the box? Or do you downgrade RouterOS to an old and wellknown version?
The latter is not generally possible. You should not downgrade RouterOS to an older version than the device came with.

Do you put only a config on the box? Or do you downgrade RouterOS to an old and wellknown version?
The latter is not generally possible. You should not downgrade RouterOS to an older version than the device came with.

Agree (although I find it strange that a newly delivered device with let's say 6.33 can not be downgraded to 6.30. This version has been an ok version in the past), in that case you should first update the device to be replaced (if possible), take an export and put it on the new device.

Agree (although I find it strange that a newly delivered device with let's say 6.33 can not be downgraded to 6.30. This version has been an ok version in the past),

MikroTik sometimes make engineering changes to devices, e.g. replacing certain chips that are no longer available with
different ones, and they add support for the new device in the RouterOS that is current at that time. When you take a device
that has been changed (and the changed serial number may be an indicator for that, I don't know), and you then install
an older RouterOS on it, the device does not work or has strange issues.

Sure it is inconvenient to those that want to keep their installed base at a common RouterOS version they have good
experience with, but you will have to live with it.

Thanks guys, some really valuable responses there.

When my box dies after the mis-configuration is there anyway to access any sort of log to get a hint of what is wrong? I can no longer connect via winbox when this occurs and i must do a reset to get the box accessible again, obviously clearing any potential log history.

Thanks in advance.

Unfortunately not. I have recently made a change request to:
- continue importing the configuration even when errors are encountered
- log the errors in a file that can be retrieved afterwards

As it is now, an error in the configuration makes it stop importing the new configuration right away,
and this often means that critical confguration items like the IP address of the ethernet interface or
the DHCP server are not processed, and the device becomes inaccessible.

The request has been noted, but of course I have no idea if and when it will be implemented.