@phil_rv 

If you use a PC with static IP address, will you see the same issue?

Yes if I assign static IP its fine. Seems to be something weird with dhcp packets on those PoE ports only.

So after checking all settings (everything was on defaults anyway) - I've done a factory reset and all is working again!

So not sure why?

Would the loop protection block do this?

If so - is there a way to see blocks and manage them?

Thanks!

@phil_rv 

Loop protection will block the port when it detects a loop. If the port is blocked, the LED of the port will shows green and orange at the same time. Normally green means 1000M speed and orange means 10/100M speed. So you can check the LED to make sure whether the port is blocked by loop protection.

It seems that loop protection is enabled by default, if you want to turn off it, you need to access the management web and access the menu Monitoring > Loop Prevention. Then choose “disabled” for this function.

If the problem happens again, maybe you can confirm the port speed and your network cable quality. TL-SG1016PE is 1000M switch. If your clients support 1000M as well, the port speed should be 1000MF. So you can check if the port gets 1000MF and please note that it needs Cat5e cable at least to get 1000M.

@Andone thank you - interesting to know that the LEDs are the only way to see blocking status.

I think my question should really have been not just if blocking a port would show the same symptoms as my original issue... but also ... is a block permanent on a port? If not - how is it cleared? Purely by disabling the overall option?

Thanks

@phil_rv 

For loop prevention, it will send a packets periodically to detect the loop. If it find the loop disappeared, the blocking port will recover. I think your problem may not related to loop prevention as well.

About the negotiation speed, did you double confirm? I think you can make you devices get 1000MF speed then observe the problem.

@Andone Thanks

I agree that the blocking is unlikely to have been the issue.

All I know is that without a change of anything physical (cables, devices, port number) that a factory reset cured the issue.

I'll probably never know what the issue was :-)

@phil_rv 

So the switch work in 100M now? Full Duplex or Half Duplex?

@Andone

Yes all working - everything plugged in the same ports. Only difference the factory reset. 

@phil_rv Really getting a bit annoyed now... Simplest operation - plugging a NAS into an unused port and same issue as before - its as if the port is blocked... packets not getting through but connecting at 1000Full Duplex... had to factory reset again to get the port working