Layer 2 transparent bridge question

RouterOS Forwarding Protocols
1

Hi

I have a more complicated setup i need some help with, we have to migrate an office with as less downtime as possible and i need some help configuring this:

I have used mikrotik routers for some time now, because every time i need a twisted solution i can use them over cisco or other brands.

The setup:

old office Lan ----------- mikrotik ------------juniper ssg20----------Internet -------- Juniper SSG20 ------ Mikrotik ----- new office lan

I am configuring a pptp between the 2 routers, but i need a layer 2 connection over it between the mikrotiks so i can have the same subnet on both locations during the movement.

The board does not want to get rid of those crappy SSG20, and those 2 routers are useless. I could maybe use at the new office only the mikrotik for the movement.

I have tried PPP tunnel bridging (BCP), Eoip, and VPLS followng this guide (don’t know mpls):

http://wiki.mikrotik.com/wiki/Transparently_Bridge_two_Networks_using_MPLS

I get a dhcp address from my old office, i can do anything inside the local subnet, but i have problems going out on the internet and i am guessing it is because of the MTU. Small pages like google.com work, but pages like microsoft.com do not.

With ping -f -l 1430 i get a reply, but bigger mtu gets discarded using BCP

I also need port forwarding to reach the servers i move in the new offices.

Basically this is a transparent bridge across 2 networks. If someone could steer me in the right direction i would really appreciate it.

Also i would like to know which is better for this job: eoip/VPLS/BCP

Thank you

2

No one can give me any ideas on this?

3

The link that you listed is to a method for bridging two sites over a wireless link. In that case the max MTU on the wireless link is higher than the typical Ethernet MTU. If you are trying to bridge two networks using that method over ISP connections/public internet then some fragmentation is to be expected. If MTUs are not set correctly on some elements then you may end up with MTU issues and a classic sign of that is some web sites working while some don’t. For example, google.com tends to keep working but yahoo.com & speedtest.net tend to give problems quickly when there are MTU problems.

4

I know it is for wireless that link, but applies to pptp link as well. I configured that tunnel over pptp since one of the mikrotiks is behind the juniper.

I tried BCP/Eoip all work inside the local network, but i need to be able to go on the internet using that tunnel from the new office. And that is my proble the MTU and i don’t know to what value to change it.