Device: RB4011iGS+
Config: https://pastebin.com/Uc8mNVX6
My configuration is currently working with ether1 connected to my fibre ONT. Since I have 2.5Gb fibre supplied and wanted to get the full speed, I purchased a 10GTek 10GB SFP+ so that I can take full advantage of my 2.5Gbe ONT.
The configuration I assumed would be relatively simple:
- update the vlan interface to use sfp-spfplus1 instead of ether1, doing the same for the "WAN"
- update dhcp client
- remove the sfp-spfplus1 interface from the bridge configuration.
I carried out these changes, rebooted. The interface is up, the DHCP client gets the static IP correctly from the ISP and my devices can ping 8.8.8.8, but nothing else seems to work. DNS resolution is broken, despite the fact the devices are bypassing the router configuration and hitting 8.8.8.8 directly. Same behaviour with the router via the terminal.
I'm a noob so I asked ChatGPT and tried a bunch of things:
- disabling the firewall rules to confirm no rule was blocking
- confirming the nat masquerade was set to the correct interface
- setting the MTU to 1480
- Set the MSS for outgoing connections : /ip firewall mangle add chain=forward protocol=tcp tcp-flags=syn action=change-mss new-mss=1360 out-interface=FastWebWAN
- Reset connection tracking : /ip firewall connection tracking reset
What possible reason could icmp to 8.8.8.8 be working and yet DNS resolution fails? The only difference is switching from ether1 to the sfp+ port.