Hi Guys

I know thi smay seem like a silly issue, but I wonder if anyone can help.
We have 2 internet connections (different providers, but both adsl), we'd like to use both (or just one!) with a mikrotik.

We use modems in bridge mode in various offices, but in this one, as soon as the modem is in bridge mode, the mikrotik can't dial the pppoe session.

If you configure the modem in router mode, then it works fine, but then you need to double nat to the mikrotik which I don't want to do.


We have tried with a TPLink 8816 and also a Draytek 120 and neither work when in bridge mode. I have tried dialing the ppp session using my laptop via the bridge modem and that does not work either.
Its like as soon as the modem is in bridge, something changes between the modem and the local exchange?

We use bridge+pppoe across many different sites, and this config is standard for us. But in this one office, it doesnt work on either of the 2 lines available.

Does anyone have any suggestions?

Thanks!

I would contact your ISP and troubleshoot. Start by getting a laptop working with the modem in bridge mode and once that works, move to the MT router. That way, you avoid making some basic mistake in your MT config.

Probably your modem configuration is wrong. Do you check the VPI and VCI config for bridge mode on your modem?

Personally, I prefer router mode for the ADSL modem because I can see the ADSL link status from the network. Frequently, I need to check the Line attenuation, SNR margin, etc that only available on the modem web interface. Using PPPoE will require you to disconnect the cable and connect it manually to your computer or switch port.

Probably your modem configuration is wrong. Do you check the VPI and VCI config for bridge mode on your modem?

Personally, I prefer router mode for the ADSL modem because I can see the ADSL link status from the network. Frequently, I need to check the Line attenuation, SNR margin, etc that only available on the modem web interface. Using PPPoE will require you to disconnect the cable and connect it manually to your computer or switch port.

This is often still possible by setting a static IP on the modem and having it route-able via the outside port on the MT.

In either case - the DSLAM should not be aware of your modem going into 'Bridge' mode.

Although there is little difference - check in your modem when in router mode, if it is doing PPPoE or PPPoA. There may be a possibility only PPPoA works but its nothing i've ever heard of.

Config one of the modems up in bridge and take it to another, known working line and try the modem. Or take a modem from a working line and try it on the troublesome one. Eliminate all possibilities.

All else fails - as mentioned - call your ISP

Hi Guys

I know thi smay seem like a silly issue, but I wonder if anyone can help.
We have 2 internet connections (different providers, but both adsl), we'd like to use both (or just one!) with a mikrotik.

We use modems in bridge mode in various offices, but in this one, as soon as the modem is in bridge mode, the mikrotik can't dial the pppoe session.

If you configure the modem in router mode, then it works fine, but then you need to double nat to the mikrotik which I don't want to do.


We have tried with a TPLink 8816 and also a Draytek 120 and neither work when in bridge mode. I have tried dialing the ppp session using my laptop via the bridge modem and that does not work either.
Its like as soon as the modem is in bridge, something changes between the modem and the local exchange?

We use bridge+pppoe across many different sites, and this config is standard for us. But in this one office, it doesnt work on either of the 2 lines available.

Does anyone have any suggestions?

Thanks!

Hi,

I have an identical situation. The only difference may be in the models of modems. Some tplink, Zyxel etc.
At one location I was able to establish the PPPoE connection on a laptop, but still does not work through MikroTik.

Did anyone find a solution?

Best,
Milos

I use a VDSL line with a Draytek 130 in bridge mode and the RB2011 setting up the PPPoE session and
it works perfectly. IPv6 too.

Did anyone find a solution?

Hi Milos,

I have no clue whether they found any solution. Regardless, I am doubtful if any solution they found for their specific setup would guarantee a solution for you.
While I can't call myself an expert, I do have some experience with bridging xDSL connections. If you would be able to give me more information about your specific setup, I might be able to help you get things working.

It would be helpful to understand the following:
Which DSL type are you using?

• ADSL(2/2+)
• VDSL(2)
• S(H)DSL
• Other

What's the multiplexing method?

• LLC-Based
• VC-Based

What is the brand/model of the xDSL modem/router that worked with the PPPoE session from the laptop?

Can you give the configuration parameters of your modem/router that worked with the PPPoE session from the laptop?

Are you able to see the PPPoE server of the provider when you use PPPoE scan feature on your PPPoE client interface?

I can't promise you I'll be able to solve your problem but I'm willing to try.

Hi Lenart,

I am so sorry for late response. I was out of work for some time.

If I understand well on every location is ADSL(2/2+) and multiplexing method LLC-Based.

On one location (location A) TP-LINK Model TD854W Ver.2 working in bridge mode. Another location (B) is same model but don't work in bridge. I don't know the version. Interesting that on (B) i can get PPPoE from laptop.

I can't see PPPoE server of the provider when you use PPPoE scan feature on location (B).

Best,
Milos

There is a staggering lack of documentation about your particular modem on the internet so I'm afraid I can't provide you with reliable info specific to that make and model.

Usually, an ADSL link is built up using the following encapsulation chain:
DSL( ATM( AAL5( RFC1483/RFC2684( Ethernet/802.3( PPPoE( PPP( IP ) ) ) ) ) ) )

In a configuration where you bridge the modem to work with an external PPPoE client, your modem is responsible for decapsulating the first four layers. RFC1483/RFC2684, also referred to as bridge mode by some manufacturers.

So, as you can see, the theory predicts that the modem spits out ethernet frames that contain PPPoE frames. And this seems to be working correctly based on your report that you are able to get a connection with your laptop. That supports the theory that there's something wrong with the settings of the RouterOS device.
The fact that you cannot see the PPPoE server in a PPPoE scan is further evidence that your RouterOS is unable to properly receive the decapsulated frames.

To analyse this problem, I would start with using my Mikrotik as a switch between my laptop and my modem to see if I could get a connection. If this fails, you could fiddle with the MTU of your interfaces to see if that is what's preventing proper communication.

Another approach to solve this issue is to use Wireshark to analyse the packet stream on your laptop when you initiate the PPPoE connection.

In addition, I would test the Mikrotik device that can't get a PPPoE connection on another ADSL link, just to rule out any issues with the device itself. You could also take a second Mikrotik device, setup as a PPPoE server, to test the PPPoE client on the Mikrotik device that's not working properly.

I would really advise you to get as much documentation as possible from your ISP with regards to the settings needed for your ADSL link.

Some useful background information can be found here:
http://www.cisco.com/c/en/us/support/do ... encap.html
https://www.farside.org.uk/200903/ipoeoatm

Hi Milos,

Call your ISP and check if they can see your Mikrotik's MAC address from xDSL port on DSLAM. I have seen couple of issues with only 1 MAC allowed on xDSL port.

Hi Milos,

Call your ISP and check if they can see your Mikrotik's MAC address from xDSL port on DSLAM. I have seen couple of issues with only 1 MAC allowed on xDSL port.

That's a good idea, it could provide some insight into where this is breaking down. I would however start by using the laptop MAC address using [/interface ethernet set ether1 mac-address=xxx], that should get around the problem.

Hi,

Thanks for all suggestions. When I get time to go to location I will try every solution. Interesting solution about MAC clone but I doubt because in the similar location (don’t have it anymore) sometime literary after one day PPPoE start working. That was nightmare, they have problem with electricity and after power outage PPPoE down and cant connect. But, after a few hours its working! Working also with laptop.

I will come back in few day with new information.

Thanks again.


Best,
Milos

i have same problem