Internet works with computer but not with router
nobodyhome1
Enthusiast - Level 2

I have spent two days trying to resolve my internet issue and I'm hoping someone here can help. I've been using Verizon Fios at home for over a decade and have never had a problem like this. Friday afternoon my internet suddenly stopped working. The connection works *fine* if I plug the ethernet cable directly into a laptop. But if the ethernet cable is plugged into any of the three routers I have, the routers cannot detect an internet connection. The internet light on the routers keeps blinking.

I can still connect via Wi-Fi to the routers with any of my wireless devices, such as that same laptop or my Android phones, so there are no wifi issues.  And again, If I plug the ethernet cable directly into the laptop I do get a working connection. The 3 routers I have cannot get an Internet connection, however.

Things I have done trying to fix this:

- I tried leaving the ethernet cable not plugged into any routers for over 4 hours hoping it was an issue with the DHCP lease.

- I've gone through the online troubleshooting steps (where they do things with your connection) at the Verizon site at least four times.

- I've talked to two Verizon representatives. I told the first one that my internet connection was working finally but it didn't realize at the time that it was only working on the laptop. The second representative I talked to told me I would have to get a Verizon router, but I've never heard of people not being able to use a third party router with Fios, so I declined.

- The second representative also said that she released the DHCP lease.

- I've tried five different ethernet cables.

- I bought a new router yesterday, which is one of the three that I have.

- I reset the new router when the second Verizon representative asked me to do so.

- I set the router to connect to Fios via dynamic IP address. When I first got Fios over a decade ago it was set up using PPPoE with a username and password. I'm assuming that's no longer necessary to do in the router since I can connect the ethernet cable directly to my laptop and get a connection.

What would cause the connection to be fine when I have the ethernet cable plugged directly into the computer, but not work at all when plugged into a router assuming it's not a DHCP lease issue? Any help with this would be greatly appreciated.

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Re: Internet works with computer but not with router
dslr595148
Community Leader
Community Leader

#1 If you are sure that you need to use DHCP and you are sure that you did not change the cable from ONT, then I believe that you need to spoof/clone the WAN MAC Address of the NAT router.

As how to / where that setting is, I would help to know at least the brand and model of the NAT router that you want to connect to the ONT. For example I have the Linksys E4200 hardware version one running Tomato firmware.

#2 Since i said WAN MAC Address, this means that you must connect the WAN/Internet/To Modem/To ONT port to the ONT.

#3 You are or are not trying to use more than one NAT router at the same time?

Re: Internet works with computer but not with router
nobodyhome1
Enthusiast - Level 2

Thank you for trying to help, I really do appreciate it. 

I've only ever used one router at a time. Both routers that I tried today were reporting in the logs that the ethernet connection was down, yet it worked fine when I plugged that same ethernet cable directly into a laptop. 

I tried cloning the Mac address from the Ethernet port on the laptop (after switching over to a Wi-Fi connection) and also from the router that was working until Friday afternoon. Neither of these allowed me to get a connection. 

The router that was working on Friday was getting an IP address through DHCP, not PPPoE. I did verify that today.

I've spent more than two days working on this constantly. I'm going to give up and get a Verizon router.  Maybe this will help them fix the issue. And then once everything is working with my router, I'll return the Verizon router. 

This has been an extremely frustrating experience. Thank you for lessening that frustration a little bit.

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Re: Internet works with computer but not with router
dslr595148
Community Leader
Community Leader

#1 Which NAT router is it / are they?

#2 You only need to use their NAT router for:

a) Fios TV One (or maybe I got that so close: Fios One TV).

b) AND OR you need support from Verizon.

Support will end at the ONT if you can get your own NAT router working...

Since you did not say anything about the TV, I take that you do not also have Fios TV.

#3 While you are using pure DHCP and not PPPoE-DHCP, not that it matters to you to much but there is also pure Static IP - however that is for businesses. I believe if residental the only way to get that is your company that you work for, helps you pay for a Static IP.

#4 Once you have their NAT router to get your NAT router working considering what you are trying to:

a) The two different NAT routers must be in different subnets. For example of what I mean by this...

If the Fios NAT router is at 192.168.1.1 and has the subnet mask of 255.255.255.0, then your NAT router if you want it to start with 192.168, then the third octets as it called can not be 1 (instead 0 or any number from 2 to 255 (ex full IP Address = 192.168.0.1).

If on the other hand: If the Fios NAT router is at 192.168.1.1 and has the subnet mask of 255.255.255.0,  and if your NAT router has any other RFC 1918 IP Address other than 192.168, you will be ok. For example there is also 172.16.0.0 to 172.31.255.255 and lastly 10.0.0.0 to 10.255.255.255

b) Only after the two NAT routers are in two different subnets, connect the WAN/Internet/To Modem/To ONT port to one of the LAN ports of the Fios NAT router.

Re: Internet works with computer but not with router
Cang_Household
Community Leader
Community Leader

Did you get IPv6 recently?

Re: Internet works with computer but not with router
dslr595148
Community Leader
Community Leader

@Cang_Household wrote:

Did you get IPv6 recently?


Unless I am missing something, their computer should work with their NAT router with IPv4.

Not to disagree with you but please explain the logic of your question since IPv4 is not being turned off yet.

Please and thank you.

Re: Internet works with computer but not with router
Cang_Household
Community Leader
Community Leader

If IPv6 and IPv4 are both on, some OS would prefer IPv6.

Coming back to the classic Intel NIC + IPv6 issue:

1) Okay when Intel NIC directly connected to the ONT.

2) Not okay when Intel NIC connected to the router, then router connected to the ONT.

I am not sure whether this points the IPv6 checksum problem to the router now instead of the ONT.

Re: Internet works with computer but not with router
dslr595148
Community Leader
Community Leader

@Cang_Household wrote:

If IPv6 and IPv4 are both on, some OS would prefer IPv6.

Coming back to the classic Intel NIC + IPv6 issue:

1) Okay when Intel NIC directly connected to the ONT.

2) Not okay when Intel NIC connected to the router, then router connected to the ONT.

I am not sure whether this points the IPv6 checksum problem to the router now instead of the ONT.


Oh ok.

In that case I suggest the OP turn off IPv6 for testing reasons. Once they know it is because of Intel NIC + IPv6, I suggest that they get a NIC that is not made by Intel, then they can use that other NIC and have IPv6 turned on.

If you disagree, please explain why.

Please and thank you

Re: Internet works with computer but not with router
smith6612
Community Leader
Community Leader

The reason there is no problem when connected to the ONT directly, is because Verizon's IPv6 network is configured to not issue /128s for devices connected directly to the ONT. Instead, the devices can perform Prefix Delegation, and grab an IP from one of the subnets that are delegated. Windows and Mac don't do that when they request an IPv6 address. They do DHCPv6, and SLAAC, expecting a /128. So the problem becomes masked.

For Intel Ethernet, see this guide: https://www.intel.com/content/www/us/en/download/19174/disabling-tcp-ipv6-checksum-offload-capabilit....  Intel provides a registry file as well as instructions for disabling IPv6 Checksum offload. Run this on any affected PC as needed until Verizon pushes fixed firmware to their Nokia ONTs. 

Re: Internet works with computer but not with router
Cang_Household
Community Leader
Community Leader

@Smith6612 wrote:

The reason there is no problem when connected to the ONT directly, is because Verizon's IPv6 network is configured to not issue /128s for devices connected directly to the ONT. Instead, the devices can perform Prefix Delegation, and grab an IP from one of the subnets that are delegated. Windows and Mac don't do that when they request an IPv6 address. They do DHCPv6, and SLAAC, expecting a /128. So the problem becomes masked.


But would this explain why using other brand's NIC, for instance Realtek's, results in Windows computers are able to connect no matter directly through the ONT, or has a router in between?

Besides end-user convenience, do RFCs call for IPv6 assignment must be done or preferred to be done one way or the other? This is just for my curiosity.