WAN kills LAN, explain please

Forums › LAN (ethernet/Wifi/routers/Bluetooth) › WAN kills LAN, explain please

Rikkitic

Awrrr
18657 posts

Uber Geek

Lifetime subscriber

#227498 9-Jan-2018 14:18

My networking know-how is limited, though usually adequate for my needs. A friend had a problem that neither of us could solve but a Vodafone magician did, with a simple suggestion. The problem was that his Internet had died and we couldn't figure out why. His router also feeds his tenants and when it was upgraded he just plugged everyone into the ports on the back, as he had done with the previous one. This worked fine for months. Then it didn't.

The VF magician asked him to look at the ports to see if any was marked WAN. One was, and as soon as he unplugged it, everything started working again.

I have a vague understanding of WAN vs LAN from the early days, but this experience has made me wonder. Why did everything work with this configuration for several months, and then suddenly stop? Why did unplugging the WAN port fix all the others? What is the practical difference between LAN and WAN in a modern router like this? I am just curious, if anyone would care to explain.

Plesse igmore amd axxept applogies in adbance fir anu typos

trig42

5809 posts

Uber Geek

ID Verified

#1932882 9-Jan-2018 14:23

Some routers (I have a TP-Link at home) that have a DSL modem, also have a WAN port (for use with Cable/Fibre instead of DSL). On my TP-Link, the WAN port also doubles as a LAN port, and you can choose what that port does in the Router setup GUI. I have Fibre, so I have my ONT connected to the WAN port on the TP-Link, therefore leaving only 3 LAN ports.

I have no idea why it worked perfectly, then suddenly stopped, other than a firmware upgrade maybe, or your friend moved some cables around/plugged something extra in?

hio77

12999 posts

Uber Geek

ID Verified

Trusted

Lizard Networks

#1932883 9-Jan-2018 14:24

Was he getting service via DSL by chance?

sounds to me like, a wire plugged into wan was showing as UP so router would have preferred that interface.

if this was plugged into something else, would be a dead loop as such.

Suspect a software update would have been pushed out setting this preference (likely to avoid the case where people upgrade to fibre and leave dsl plugged in and then complain about slow speeds on their new fibre)

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

wellygary

8312 posts

Uber Geek

#1932895 9-Jan-2018 14:52

Rikkitic:

Why did everything work with this configuration for several months, and then suddenly stop?

Something on the network probably got updated, or rebooted and then went off looking for the network to pick up a new IP address or the like.....

Rikkitic

Awrrr
18657 posts

Uber Geek

Lifetime subscriber

#1932897 9-Jan-2018 14:53

Sorry, I should have been clearer. My lack of know-how is showing.

He does not have fibre. There is a little uncertainty as to what he has now. Initially it was ADSL, but a VF technician said it had been upgraded to VDSL. I think that is also why he was given the new router. But then someone else at VF said he was still on ADSL, so we are not completely clear on that.

It is quite possible that the one tenant who had the WAN connection did something that killed the rest. Or maybe it was a firmware update. I don't know and I don't know how to find out. It is also possible that the WAN link never worked and the tenant just didn't complain for some reason. The only thing I know for sure is the Internet connection stopped functioning for everyone yesterday after it had been working fine for some months, and unplugging the WAN connection suddenly made it work again. I was just curious what kind of interaction might be going on here.

Plesse igmore amd axxept applogies in adbance fir anu typos

kobiak

1615 posts

Uber Geek

Trusted

#1932904 9-Jan-2018 15:00

in simple terms:

WAN for incoming connection which to be shared

LAN for outcoming connection which is used from shared

WAN port could be configured as LAN on MOST routers.

So either router was reset to default, or change of settings caused it.

router received something on WAN and broadcast on LAN and internet went meh because of routing issue.

helping others at evgenyk.nz

hio77

12999 posts

Uber Geek

ID Verified

Trusted

Lizard Networks

#1932963 9-Jan-2018 16:23

i would get them a 8 port gbit switch to stick off the modem and call it a day.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

Rikkitic

Awrrr
18657 posts

Uber Geek

Lifetime subscriber

#1932968 9-Jan-2018 16:39

According to my mate (I haven't been physically present throughout all this) the magic VF lady has promised to ship him a new modem with an extra LAN port. I did think about the switch but if VF is willing to do this I guess that also solves the problem.

Plesse igmore amd axxept applogies in adbance fir anu typos

Equinox IT

Cloud spending continues to surge globally, but most organisations haven’t made the changes necessary to maximise the value and cost-efficiency benefits of their cloud investments. Download the whitepaper From Overspend to Advantage now.

hio77

12999 posts

Uber Geek

ID Verified

Trusted

Lizard Networks

#1932974 9-Jan-2018 16:43

Did not know vodafone had such a thing... i do question.... but... ala... we will wait and see :)

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

johny99

495 posts

Ultimate Geek
Inactive user

#1933039 9-Jan-2018 18:33

I would second @hio77 idea

yitz

2074 posts

Uber Geek

#1933040 9-Jan-2018 18:39

Going from the HG659 to the Vodafone Ultra Hub you would lose 1 Ethernet port in total...

hio77

12999 posts

Uber Geek

ID Verified

Trusted

Lizard Networks

#1933043 9-Jan-2018 18:48

yitz: Going from the HG659 to the Vodafone Ultra Hub you would lose 1 Ethernet port in total...

Ah i didn't realize it had a dual purpose port...

would totally explain things then! the setting has been switched from ETH to WAN.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.