Mikrotik routing issue with PPPOE

RouterOS General
1

Good day

I have an issue which is hard to solve by me or even to understand it. Below is a brief description of it:
Mikrotik RB751g-2Hnd
Router OS 6.43.2
Provider access - dual PPPOE
Following configuration used for last 6 years

/interface pppoe-client
add add-default-route=yes disabled=no interface=wan name=pppoe-internet \
    password=password use-peer-dns=yes user=user
set pppoe-internet disabled=no
 
/interface pppoe-client
add add-default-route=yes interface=wan name=pppoe-internet use-peer-dns=yes

Last few weeks I’m loosing internet access with the following test case:

  1. From the situation when everything is fine - get IP and routing using DHCP for internal provider network and another IP for internet access with its routing
  2. Getting NAK lost internal IP address from DHCP server and getting new one, routing tables rebuilt
  3. No access to the internet, all internet requests goes to internal network

Steps helping me to solve the issue:

  1. Disable PPPOE connection
  2. Disable WAN connection
  3. Enable WAN connection - wait for IP and routing
  4. Enable PPPOE connection - everything is working.

Just to disable/enable PPPOE is not enough.
Looking for any suggestion how to dig into this issue and solve it. Thanks for advice’s.

2

What for you need network from dhcp server?
What for you need network from pppoe server?

3

DHCP network is for IGMP - IP TV
PPPoE network is for Internet access

4

How is looks like your route list after receiving IPs from PPPoE and DHCP server?

5

Normally it looks like following.
https://photos.app.goo.gl/4cg9RtkVm58DqpX57
After NAK IP lost - no visual difference

6

Issue reproduced again.
routing just after it https://photos.app.goo.gl/wwnb7vo9N463Ryue7

Routing after W/A described above - https://photos.app.goo.gl/gMakMek72rXSetAh8

7

How is looks like your route list after receiving IPs from PPPoE and DHCP server?

Yes - this how dual PPPOE works. I’ve 2 IPs

8

Both default routes have the same distance (1), so which one is used depends on the order in which they are seen. The distance used to be zero on DHCP/PPPoE client interfaces which technically was incorrect as distance of 0 should only be used on directly connected interfaces
6.40.6 *)route - fixed DHCP/PPP “add-default-route” “distance” minimal value to 1
Upgrading to this version and later didn’t change the distance for existing DHCP and PPPoE client interfaces, but if edited they can’t be saved unless the distance is changed to >0, and reloading from a brief (not verbose) .rsc file will create interfaces with different settings to before.

I suspect you don’t need the default route supplied by DHCP at all - try disabling it.

9

Your ISP made a mistake. He shouldn’t give you default route as IPTV ISP.

10

Thank a lot. Will try to solve it with ISP or some custom routes. My question covered.

11

I’m sorry, I did a stupid mistake. You should bridge your uplink port to ISP and downlink port to your IPTV set top box equipment. Your STB should get IP from ISP, not your router.

12

It’s hard to do cause I don’t have any STB. My Smart TVs has only ISP plugin installed to catch and show IGMP traffic. They couldn’t get and support any type of routing.

13

Your smart tv has to have net driver. It has to assign IP with dhcp client.