I googled a lot of this problem with no luck, actually I didn't find anyone with similar situation.
My problem is in general, that PS3 discovers PMS without any problem on WLAN, but once I configure it for ethernet connection it can't find it.
I'm sure that network settings are correct, have followed FAQ, and there were no specific tips which could help me.
I'm using 192.168.0.0/24 network, PS3 has fixed ip .120 and is pingable from my PC both WLAN and LAN, it also successfully connects to internet on both connections.
On PC there is no firewall, but PC should be clear as it is working on WLAN.
On router firewall is turned off UPnP is turned on, no other possibly harmful settings turned on.
Are you able to give me some advices or point me in right direction? I don't have different router to check or any switch, unfortunately.