Configuring network for use with two routers

[maytiffins]

I am running into some problems when trying to connect two routers to my existing internet connection - I have two TG797n v3 routers which I am trying to run separate networks on.

The existing setup consists of a switch connected to the ISP modem. The two routers are plugged into the switch. This works reliably when one of them is not connected.

I have read other threads which suggest that the ISP only provides one public address, however a friend of mine is having no problems connecting two public IP address using his modem with the same setup I described - he even connected a third router and it was assigned another public IP.

We are both using the NBN however we have different providers, this could be the issue. I have not looked up resources relating to this directly. However, I want to make sure that it is not my setup before thinking about switching providers.

Setup of the routers: The first router is setup with a DHCP server while the second has been disabled as the ranges overlap and are not configurable with the newer firmware. I could set the first router's range however I don't think this should be a problem. I have connected the required devices via a static connection outside of the range of the first router - all devices can connect to their respective routers fine.

When both routers are connected to the switch, the internet connection is established with the router with newer firmware. After about 3-4 minutes the router with older firmware establishes a connection and the other one drops out. After another minute both connections are lost and do not recover.

Is there some configuration that I am missing? I cannot find any difference in configurations between me and my friend's setup apart from the routers.

 

[padraig92]

I am running into some problems when trying to connect two routers to my existing internet connection - I have two TG797n v3 routers which I am trying to run separate networks on.

The existing setup consists of a switch connected to the ISP modem. The two routers are plugged into the switch. This works reliably when one of them is not connected.

I have read other threads which suggest that the ISP only provides one public address, however a friend of mine is having no problems connecting two public IP address using his modem with the same setup I described - he even connected a third router and it was assigned another public IP.

We are both using the NBN however we have different providers, this could be the issue. I have not looked up resources relating to this directly. However, I want to make sure that it is not my setup before thinking about switching providers.

Setup of the routers: The first router is setup with a DHCP server while the second has been disabled as the ranges overlap and are not configurable with the newer firmware. I could set the first router's range however I don't think this should be a problem. I have connected the required devices via a static connection outside of the range of the first router - all devices can connect to their respective routers fine.

When both routers are connected to the switch, the internet connection is established with the router with newer firmware. After about 3-4 minutes the router with older firmware establishes a connection and the other one drops out. After another minute both connections are lost and do not recover.

Is there some configuration that I am missing? I cannot find any difference in configurations between me and my friend's setup apart from the routers.

Majority of residential ISPs will only provide 1 public IP address which is provisioned via a DHCP server.

What kind of Internet connection are you using? DSL? If so, are you using the same PPP authentication details on both routers?

 

[maytiffins]

Majority of residential ISPs will only provide 1 public IP address which is provisioned via a DHCP server.

What kind of Internet connection are you using? DSL? If so, are you using the same PPP authentication details on both routers?

We have fibre to the premises so they're running IPoE

 

[padraig92]

Majority of residential ISPs will only provide 1 public IP address which is provisioned via a DHCP server.

What kind of Internet connection are you using? DSL? If so, are you using the same PPP authentication details on both routers?

We have fibre to the premises so they're running IPoE

IPoE doesn't use any subscriber authentication mechanisms I believe, unless your ISP is using some 802.1X authentication mechanism on the DHCP services?

Either way both routers will perform a DHCP discover message to try pick up an IP address from the ISP. Your ISP might limit the scope to 1 IP address for that subscriber service (which is more than likely because IPv4 public addresses have all ran out so preserving them is quite vital for ISPs)

Have you tried logging into both routers at the same time and see if both devices pick up a public IP address?

 

[maytiffins]

Majority of residential ISPs will only provide 1 public IP address which is provisioned via a DHCP server.

What kind of Internet connection are you using? DSL? If so, are you using the same PPP authentication details on both routers?

We have fibre to the premises so they're running IPoE

IPoE doesn't use any subscriber authentication mechanisms I believe, unless your ISP is using some 802.1X authentication mechanism on the DHCP services?

Either way both routers will perform a DHCP discover message to try pick up an IP address from the ISP. Your ISP might limit the scope to 1 IP address for that subscriber service (which is more than likely because IPv4 public addresses have all ran out so preserving them is quite vital for ISPs)

Have you tried logging into both routers at the same time and see if both devices pick up a public IP address?

There is no authentication on the DHCP service.

When connecting with both routers at the same time, they connect one after the other as mentioned in the original post. They each pick up on a different public IP address.

 

[failboat]

Buy a small switch and plug the modem into that and then all the WAN sides of your routers. If you have a pfsense box or proxmox you can run multiple routers on one box and not need the switch. To make sure they keep the same ip make it static on WAN for each one.

With PPPOE the ISP can send multiple IPs to you over one line. You just have to bridge it on your side.

 

[mastermoders]

Since you're using IPoE with your NBN connection, there is a quick way you can test if your ISP is able to assign you with multiple IPv4 addresses

Plug your switch into your NBN modem (the one NBN co. install fibre directly to) and then connect a couple of computers to that. If only one computer is able to have internet access at once then you can only be assigned one public IP. If two work you can have two... etc etc.

If you're looking to connect the two routers together still, with the same public IP, plug the modem into the WAN port on your first router then connect the WAN port on your second router to any on the first. You may have some issues with the DHCP servers but the TG797n v3 supports manual setup at least with the latest firmware. Then you'll have a spare switch for more connections

Hope this helps