Mikrotik How To

Overview
Ethernet over IP (EoIP) Tunneling is a MikroTik RouterOS protocol that creates an Ethernet tunnel between two routers on top of an IP connection. The EoIP interface appears as an Ethernet interface. When the bridging function of the router is enabled, all Ethernet level traffic (all Ethernet protocols) will be bridged just as if there where a physical Ethernet interface and cable between the two routers (with bridging enabled). This protocol makes multiple network schemes possible.

Network setups with EoIP interfaces:

* Possibility to bridge LANs over the Internet
* Possibility to bridge LANs over encrypted tunnels
* Possibility to bridge LANs over 802.11b 'ad-hoc' wireless networks

Specifications
Packages required : None
License required : Basic (DEMO license is limited to 4 tunnels)
Home menu level : /interface eoip
Standards and Technologies : GRE (RFC1701)
Hardware usage: not significant
Related Documents
Software Package Installation and Upgrading
IP Addresses and Address Resolution Protocol (ARP)
Bridge Interfaces
PPTP (Point to Point Tunnel Protocol) Interface
Description
An EoIP interface should be configured on two routers that have the possibility for an IP level connection. The EoIP tunnel may run over an IPIP tunnel, a PPTP 128bit encrypted tunnel, a PPPoE connection, or any connection that transports IP.

Specific Properties:

* Each EoIP tunnel interface can connect with one remote router which has a corresponding interface configured with the same 'Tunnel ID'.
* The EoIP interface appears as an Ethernet interface under the interface list.
* This interface supports all features of and Ethernet interface. IP addresses and other tunnels may be run over the interface.
* The EoIP protocol encapsulates Ethernet frames in GRE (IP protocol number 47) packets (just like PPTP) and sends them to the remote side of the EoIP tunnel.
* Maximal count of EoIP tunnels is 65536.

EoIP Setup
Submenu leve : /interface eoip
Property Description
name (name; default: eoip-tunnelN)- interface name for reference
mtu (integer; default: 1500) - Maximum Transmission Unit. The default value provides maximal compatibility
arp (disabled | enabled | proxy-arp | reply-only; default: enabled) - Address Resolution Protocol
tunnel-id (integer; default: 0) - a unique tunnel identifier
remote-address - the IP address of the other side of the EoIP tunnel – must be a MikroTik router
Notes
tunnel-id is method of identifying tunnel. There should not be tunnels with the same tunnel-id on the same router. tunnel-id on both participient routers must be equal.

mtu should be set to 1500 to eliminate packet refragmentation inside the tunnel (that allows transparent bridging of ethernet-like networks, so that it would be possible to transport full-sized ethernet frame over the tunnrl).
Example
To add and enable an EoIP tunnel named to_mt2 to the 10.5.8.1 router, specifying tunnel-id of 1:

[admin@MikroTik] interface eoip> add name=to_mt2 remote-address=10.5.8.1 \
\... tunnel-id 1
[admin@MikroTik] interface eoip> print
Flags: X - disabled, R - running
0 X name="to_mt2" mtu=1500 arp=enabled remote-address=10.5.8.1 tunnel-id=1

[admin@MikroTik] interface eoip> enable 0
[admin@MikroTik] interface eoip> print
Flags: X - disabled, R - running
0 R name="to_mt2" mtu=1500 arp=enabled remote-address=10.5.8.1 tunnel-id=1

[admin@MikroTik] interface eoip>

EoIP Application Example
Let us assume we want to bridge two networks: 'Office LAN' and 'Remote LAN'. The networks are connected to an IP network through the routers [Our_GW] and [Remote]. The IP network can be a private intranet or the Internet. Both routers can communicate with each other through the IP network.

Our goal is to create a secure channel between the routers and bridge both networks through it. The network setup diagram is as follows:



To make a secure Ethernet bridge between two routers you should:

1. Create a PPTP tunnel between them. Our_GW will be the pptp server:

[admin@Our_GW] interface pptp-server> /ppp secret add name=joe service=pptp \
\... password=top_s3 local-address=10.0.0.1 remote-address=10.0.0.2
[admin@Our_GW] interface pptp-server> add name=from_remote user=joe
[admin@Our_GW] interface pptp-server> server set enable=yes
[admin@Our_GW] interface pptp-server> print
Flags: X - disabled, D - dynamic, R - running
# NAME USER MTU CLIENT-ADDRESS UPTIME ENC...
0 from_remote joe
[admin@Our_GW] interface pptp-server>

The Remote router will be the pptp client:

[admin@Remote] interface pptp-client> add name=pptp user=joe \
\... connect-to=192.168.1.1 password=top_s3 mtu=1500 mru=1500
[admin@Remote] interface pptp-client> enable pptp
[admin@Remote] interface pptp-client> print
Flags: X - disabled, R - running
0 R name="pptp" mtu=1500 mru=1500 connect-to=192.168.1.1 user="joe"
password="top_s2" profile=default add-default-route=no

[admin@Remote] interface pptp-client> monitor pptp
status: "connected"
uptime: 39m46s
encoding: "none"

[admin@Remote] interface pptp-client>

See the PPTP Interface Manual for more details on setting up encrypted channels.

2. Configure the EoIP tunnel by adding the eoip tunnel interfaces at both routers. Use the ip addresses of the pptp tunnel interfaces when specifying the argument values for the EoIP tunnel:

[admin@Our_GW] interface eoip> add name="eoip-remote" tunnel-id=0 \
\... remote-address=10.0.0.2
[admin@Our_GW] interface eoip> enable eoip-remote
[admin@Our_GW] interface eoip> print
Flags: X - disabled, R - running
0 name=eoip-remote mtu=1500 arp=enabled remote-address=10.0.0.2 tunnel-id=0
[admin@Our_GW] interface eoip>

[admin@Remote] interface eoip> add name="eoip" tunnel-id=0 \
\... remote-address=10.0.0.1
[admin@Remote] interface eoip> enable eoip-main
[admin@Remote] interface eoip> print
Flags: X - disabled, R - running
0 name=eoip mtu=1500 arp=enabled remote-address=10.0.0.1 tunnel-id=0

[Remote] interface eoip>

3. Enable bridging between the EoIP and Ethernet interfaces on both routers.

On the Our_GW:

[admin@Our_GW] interface bridge> add forward-protocols=ip,arp,other \
\... disabled=no
[admin@Our_GW] interface bridge> print
Flags: X - disabled, R - running
0 R name="bridge1" mtu=1500 arp=enabled mac-address=00:00:00:00:00:00
forward-protocols=ip,arp,other priority=1

[admin@Our_GW] interface bridge> port print
Flags: X - disabled
# INTERFACE BRIDGE
0 eoip-remote none
1 office-eth none
2 isp none

[admin@Our_GW] interface bridge> port set "0,1" bridge=bridge1

And the same for the Remote:

[admin@Remote] interface bridge> add forward-protocols=ip,arp,other \
\... disabled=no
[admin@Remote] interface bridge> print
Flags: X - disabled, R - running
0 R name="bridge1" mtu=1500 arp=enabled mac-address=00:00:00:00:00:00
forward-protocols=ip,arp,other priority=1

[admin@Remote] interface bridge> port print
Flags: X - disabled
# INTERFACE BRIDGE
0 ether none
1 adsl none
2 eoip-main none

[admin@Remote] interface bridge> port set "0,2" bridge=bridge1

4. Addresses from the same network can be used both in the Office LAN and in the Remote LAN

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