Tp-link tl-wr740n v4.28 Using a Lan port as Wan

Hi to all,

We have an tp-link tl-wr740n v4.28 router at our home unfortunately it's wan port is dead after streak of lightning. We want to use one of the lan ports as a wan port. We gave it a try with OpenWrt and edit some settings in switch and interface categories and but we can not establish a stable connection it disconnects and reconnects every other second. Our connection protocol is pppoe. Can you share with us if you now the correct configuration for this. If you help us we would appreciate it because we can't afford a new router for now. We searched for it for hours but we cannot find a proper configuration for this purpose that's why I am writing here. I hope it is correct place.

Thanks in advance.

Are you certain that you removed the chosen port from the LAN VLAN?

Hi Ileachii,

There is tagged, untagged and off options in the switch menu we just reversed the configuration of one of the lan port. But we do not know how exactly the port layout of this router or what exactly these tagging is. If you did this before can you share your configuration that we can apply it to our one.

Ports that connect to an ordinary device that expects untagged packets should be set as untagged in one VLAN and off in all the others.

There may be hardware damage to other ports or the whole switch. The link lights on the port and on the modem should stay on continuously while the cable is plugged in no matter how the VLANs are set.

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Thanks for the reply,

The lights are OK but although we achieved pppoe via one of the lan ports it keeps disconnecting so there is no fluent internet connection. We tried all 4 Lan ports. When we set untagged all Lan ports and plug the internet cable from wall to one of Lan the ports we can connect internet from other ports via windows with pppoe authentication so we assumed Lan ports are OK but we are not sure about nothing at all as we did nont understand how that ports exacty connect each other and eth denotations.

What is the configuration for a Lan port to operate as a Wan port and what is the adjustments required in openWrt GUI like switch, interfaces etc.

Hi all,

I am experiencing similar issue. I have TP-Link WR740 router with dead WAN port.
I divided the switch in two vlans. I set port 4 as VLAN0.2 and all the rest as VLAN0.1
VLAN0.1 was already assigned to LAN interface (bridged together with Wireless).
I put the ISP cable in port 4 and the internet comes to my phone via wireless, however I have no internet connection on my desktop via Ethernet cable. I got IP address by DHCP, however I have no internet. Even more I could not access the router anymore via the cable.
The strange thing is that when I remove the ISP cable from the "WAN" port I can access the router without any issues via the wire on my desktop.
It seems to me that there is something wrong with the switch when LAN and WAN cables are connected.
Any clue on this ?

When you use VLANs on an ethernet port you must have everything connected to a specific VLAN: eth0.1 or eth0.2 instead of plain eth0. Plain eth0 will still appear in lists but you should connect no interfaces to it.

When a router has been hit by lightning enough to kill one of the Ethernet ports you should consider that there may be more subtle hardware problems in another area.

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