my MTU=9000 setting, C4500 communicates flawlessly to the Internet (MTU=1488). but doesn't with NAS on the port back. I wanted the people with the same experience. OK. thanks. I understood the place...

thanks. but I don't say about jumbo frame. OK.

If it fallbacks to MTU=1500, it's OK. that should be. I mean C5400 should responde to Path MTU Discovery, but I suspect it. I said "no communication". that means I can't access the server. Connecting...

that isn't what I mean... something relating Path MTU Discovery

Model : Hardware Version : Firmware Version : ISP : hi, I have a NAS. I set the NAS MTU bigger than 1500 (e.g. 4000). And my iMacs are set in MTU 9000. When I connect the NAS in LAN, it works: imac...