Dear All,
Maybe somebody had a similar setup. We have two RB750 routers, connected via Openvpn in ethernet mode.
Openvpn is bridged with ether2 interface on both RB750s. Each side has a PC connected to ether2.
One PC has assigned IP 10.10.10.1/24 and another one 10.10.10.2/24.
We try to ping from one PC to another one with ping size 1457 (total frame size 1499) and it goes through.
When we increase the icmp payload size up to 1458 ( total frame 1458+ 8 icmp + 20 ip + 14 ethernet=1500 bytes), it fails.
We tried to capture the frames on the reception side and could see 16 bytes Trailer option added to Ethernet frame, so its size increased drastically while traversing Openvpn link. We tried to play with both 4.x and 5.2 RouterOS firmwares without any luck.
Your suggestions would be appreciated.