Correct MTU size ...
- Thread starter TBru
- Start date
Hello I would set 1412, even though its very strange that your router only has mtu 1412? If you trying to ping the router from cli, make sure you do ping with
ping -M do -s 1384 IP-OF-YOUR-ROUTER because you need to do 28 Bytes less (vlan, vXLAN ...)Router has PPPOE so 1412 is my current MTU setting or shoud i set proxmox external NET to 1384 instead ? I also read about 9000 MTU on both BRIDGE and NETWORK card ... ps. should be setting inside VM also 1384 instead of 1412 ? I'm confused as MTU should be always include overhead ?
Hi, if the router wil still be in place with your pve setup and the router will do the PPPoE, and your pve host is connected to an eth port of the router and the router and it's pppoe connection is configured right, then normally you don't have to change MTU, just leave it at 1500 default, the router should handle the fragmentation. Also for the VMs...
Do you block all ICMP on PVE side? If yes, you shouldn't - fe PMTU (path mtu) discovery can fail. Do you know the MTU your internetprovider can deliver? Is the router managed by your provider, because if router would do all right with MTU yo shouldn't have to even think about it on your side, if you are just using the IPs, without any fancy tunnels or VPN....
Firewall on PVE is currently off. Firewall in VM is blocking ICMP except necessary ping and pmtu is on. router is managed by provider, i dont know the max MTU he can deliver but will investigate. i use a vpn tunnel to external and have configured a specific mtu for that (i know the vpn troubles).