Did you remove the VLAN ports on the TL-SG105E from the Default VLAN? Are you using different broadcast domains for each VLAN? What about posting a scrennshot of the TL-105E settings here so we can see how it has been configured?

This setup looks correct, except that I don't get the point why you are forwarding unused VLANs to the TL-SG105E. You wrote that different MAC addresses appear at the main switch port to which the TL-SG105E is connected to. But if this port is defined as a trunk port for all VLANs, all frames in those VLANs are forwarded to the TL-SG105E on egress. That's perfectly correct behavior.

However only the MAC addresses of devices connected to the TL-SG105E ports 1, 2, 3 and 4 should appear on ingress at the main switch port connected to the TL-SG105E. Where else should frames with MAC adresses from other devices come from via the TL-SG105E? If I understand correctly, there are only 4 devices connected to the TL-SG105E, right?

Anyway, if the main switch's trunk port is member of the same (unused) VLANs listed above for the TL-SG105E too, then those frames are indeed appearing on egress to the TL-SG1015E, no matter whether there is an "access" port defined for such an unused VLAN or not. Note that the VLAN standard doesn't even define the terms "access" or "trunk" port - it just defines "ports which are member of only one network" and "ports which are member of more than one network". That's why every port - access or trunk - has always the same behavior: they are just ports, the former characterized by being in one (and only one) VLAN, the latter being characterized by being in more than one VLAN. Thus, if the main switch's port used as "trunk" is a member of all VLANs, frames arriving elsewhere on your main switch are being forwarded to the port the TL-SG105E is connected to.

I still don't get the point why you are forwarding traffic for all other VLANs except 17, 185 and maybe a third VLAN for management of the switch when they are not used for any other port. What is the purpose of passing all VLANs to the TL-SG105E if they terminate at the switch? I would understand if you would use two trunks on TL-SG105E to build a chain to other switches, but this is not how it is configured.

Tobias8250 wrote

We have several devices of this switch and so me made a default configuration. The unused VLAN's are "small" networks so there isn't a lot of traffic. Anyway Unicast traffic shouldn't be send to the switch or did I get this wrong? So there is only Broad- and Multicast.

VLAN ist just a technique to have more than one network using the same physical infrastructure (cables/switches/routeres), nothing else. Of course, Unicasts, Broadcasts and Multicasts inside each network are supposed to be sent over the assigned VLAN(s), too.

Note that if you implement one Broadcast domain spanning several different VLANs, Broadcasts are sent to all of those VLANs if they are connected at any point (router, switch). To make a VLAN a single Broadcast domain, use different subnet IPs for each VLAN, which is reommended anyway except in special setups like Multi-Tenant Unit (MTU) VLANs supported by TL-SG 105E switches, too.

So probably you see MAC addresses in your VLAN 185 because of a common broadcast domain. I would suggest to keep the number of VLANs as small as needed, which includes to only configure those VLANs on a switch, which actually have a destination (non-VLAN end-point or trunk connection to another switch/server) on this switch.