Mikrotik bandwidth test connection error message that reads “can’t connect to host” can be frustrating when trying to determine the throughput on a wireless link. Apart from not being able to test from the affected device, further checks will reveal that the LAN interface is under-performing.
At the time of writing this article, there is no material anywhere else on the causes and solution to this problem. However, as frustrating as the Mikrotik bandwidth test connection error problem can be, the solution is quite simple and easy to implement. First, let’s look at the cause of this problem.
Why Mikrotik bandwidth test connection error?
There are two main types of Mikrotik bandwidth test error messages that a user can receive while attempting to perform a bandwidth test. One is authentication error and the other is connection error. Authentication errors are caused by entering the wrong server login credentials and can simply be corrected by typing in the correct username and password of the device you are testing to. The latter is caused by interface duplex mismatch that affects the overall performance of your link and is what this article is about. Read on.
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It is very easy to find cheap 10/100 switches on so many networks today. This is because most people do not want to spend money on network infrastructures let alone on a switch; a plug-and-play device. The Mikrotik bandwidth test connection error is caused when a Mikrotik radio with 10/100/1000 ethernet port negotiates a 10mbps connection on a switchport. This happens because the interface negotiation on Mikrotik devices is set to auto by default. Once this happens, two major issues will arrise. Firstly, performing bandwidth test on the affected device to any other Mikrotik device will display an error message saying “can’t connect to host”. However, test from other devices to the wireless interface of the affected Mikrotik device will work. Secondly, the speed on the affected LAN port will not go beyond 10mbps.
Solution to Mikrotik bandwidth test connection error
To resolve Mikrotik bandwidth test connection error on a Mikrotik device, simply go to interfaces and double-click on the LAN port, click on ethernet and uncheck the box for 10mbps on both tx and rx. If you have a gigabit switch, you can uncheck the box for 100M to force a gigabit interface negotiation. See image below.
After performing the task above, the Mikrotik device LAN port will renegotiate interface speed with the LAN switch and connection will be re-established. Bandwidth test from the device to other devices will work effectively and speed test from the LAN will no longer be limited to 10Mbps.