Allied Telesis AT-WR4500 manual Static Equal Cost Multi-Path routing

AT-WR4500 Series - IEEE 802.11abgh Outdoor Wireless Routers	113
RouterOS v3 Configuration and User Guide

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You can use policy routing even if you use masquerading on your private networks. The source address will be the same as it is in the local network. In previous versions of RouterOS the source address changed to 0.0.0.0

It is impossible to recognize peer-to-peer traffic from the first packet. Only already established connections can be matched. That also means that in case source NAT is treating Peer-to-Peer traffic differently from the regular traffic, Peer-to-Peer programs will not work (general application is policy- routing redirecting regular traffic through one interface and Peer-to-Peer traffic - through another). A known workaround for this problem is to solve it from the other side: making not Peer-to-Peer traffic to go through another gateway, but all other useful traffic go through another gateway. In other words, to specify what protocols (HTTP, DNS, POP3, etc.) will go through the gateway A, leaving all the rest (so Peer-to-Peer traffic also) to use the gateway B (it is not important, which gateway is which; it is only important to keep Peer-to-Peer together with all traffic except the specified protocols).

Example

To add the rule specifying that all the packets from the 10.0.0.144 host should lookup the at routing table:

[admin@AT-WR4562] ip firewall mangle add action=mark-routing new-routing-mark=at \ \... chain=prerouting

[admin@AT-WR4562] ip route> add gateway=10.0.0.254 routing-mark=mt

[admin@AT-WR4562] ip route rule> add src-address=10.0.0.144/32 \ \... table=mt action=lookup

[admin@AT-WR4562] ip route rule> print Flags: X - disabled, I - invalid

0src-address=192.168.0.144/32 action=lookup table=mt [admin@AT-WR4562] ip route rule>

5.4.4 Application Examples

Static Equal Cost Multi-Path routing

Consider the following situation where we have to route packets from the network 192.168.0.0/24 to 2 gateways - 10.1.0.1 and 10.1.1.1:

ISP 1 ISP 2

10.1.0.1/28		10.1.1.1/28
	2 Mbps	4 Mbps

Interface: Public1 Interface: Public2

IP: 10.1.0.2/28 IP: 10.1.1.2/28

Interface: Local

IP: 192.168.0.1/24

192.168.0.0/24

Figure 16: Static Equal Cost Multi-Path Routing example