multiwan: Connection to spare internet provider

• Main uplink -- connection to main internet provider.
• Spare link -- connection to router of the friendly organisation.
• Main condition -- subnets of the local network, Main uplink and Spare link do not overlap each other.

Download OpenWRT for your device. Follow instructions in generic.flashing and walkthrough_login.

If you are installing a trunk version, it's recommended to install also the web user interface LuCI for ease of operations. Current version should have the web user interface already installed and enabled by default.

Next to be installed is the luci-app-miltiwan package that in turn will pull also the dependencies like the required multiwan_package.

LuCI: fill all required fields on Network → Interfaces → WAN and click Save & Apply UCI: edit a file /etc/config/network:

config interface 'wan'
        option ifname 'eth1'
        option proto 'static'
        option ipaddr '198.51.100.195'
        option netmask '255.255.255.128'
        option gateway '198.51.100.129'
        option dns '192.0.2.160 8.8.8.8 192.0.2.190'

And apply changes:

/etc/init.d/network reload

It is recommends specify some public DNS in addition to DNS of provider “Main aplink”. It is need to avoid failures of resolving when Main uplink will down.

First, it is need exlude one port from existing “LAN” VLAN. This VLAN has number “1”. Second, need create new VLAN (with number “2” or another less or equal 4096) and include into new VLAN freed port with untagged mode and Port 5 (“CPU port”) in the tagged mode.

In UCI: change file /etc/config/network: replace

config switch_vlan
        option device 'rtl8366s'
        option vlan '1'
        option ports '0 1 2 3 5t'

with

config switch_vlan
        option device 'rtl8366s'
        option vlan '1'
        option ports '0 1 2 5t'
config switch_vlan
        option device 'rtl8366s'
        option vlan '2'
        option ports '3 5t'

After /etc/config/network is changes it is need to run:

/etc/init.d/network restart

for apply changes.

It is need assign virtual interface to phisical. LuCI: Network → Interfaces:

• Click Add New Interface
• Write name WWAN
• Select phisical interface “VLAN interface: eth0.2”
• In a line Protocol of the new interface select DHCP Client (or required by Spare link)
• Click Submit

UCI: Add following lines into /etc/config/network:

config interface 'wwan'
        option ifname 'eth0.2'
        option proto 'dhcp'

Set up firewall parameters for new interface:

• LuCI: Network → Interfaces → WWAN → Firewall settings select a zone “wan”.

In LuCI: Network → Multi-WAN

• Remove WAN2
• Create WWAN
• Set Failover Traffic Destination to another interface: WAN in wwan interface section and WWAN in wan section
• Best solution for DNS: insert DNS server of provider of link and one of public save DNS server (for example, Google's public DNS servers)
• A parameter Health Monitor ICMP Host(s) should be set with different save servers but not servers of provider of links (because link may be up but internet are down)

Next assign policy for multiwan:

• Default Route: wan

(Main uplink should use for all traffic if it up, and Spare link only in case when Main uplink are down.

Last remove unneeded rules from Multi-WAN Traffic Rules and enable multiwan.

Don't forget click Save & Apply.

In UCI need change /etc/config/multiwan:

config multiwan 'config'               
        option enabled '1'
        option default_route 'wan'
                                          
config interface 'wan'                    
        option weight '10'                
        option health_interval '10'       
        option timeout '3'                
        option health_fail_retries '3'    
        option health_recovery_retries '5'
        option dns 'auto'           
        option icmp_hosts '8.8.8.8'   
        option failover_to 'wwan'         
                                          
config interface 'wwan'                   
        option weight '10'                
        option health_interval '10'       
        option timeout '3'                
        option health_fail_retries '3'    
        option health_recovery_retries '5'
        option dns 'auto'                 
        option icmp_hosts '8.8.4.4'
        option failover_to 'wan'          

Next apply changes:

/etc/init.d/multiwan restart

LuCI: Network → DHCP and DNS → General settings. In section DNS forwardings enumerate DNS servers of both links and, for better work, one or two public DNS servers.

UCI: enumerate DNS servers in lines list server … in section config dnsmasq of file /etc/config/dhcp, for example:

config dnsmasq
	list server '8.8.8.8'
	list server '8.8.4.4'
	list server '192.0.2.160'
	list server '192.0.2.190'
…

And apply changes:

/etc/init.d/dnsmasq reload

Just work!