AP mode with LTE usb dongle

Installing and Using OpenWrt
1

Dear all,

I have an device, it run openwrt OS.
My device will connect to Home router via LAN0 port, and device also support internet over usb lte dongle.
My device able ping to internet via LTE dongle or LAN cable.
It want to create an AP for user, AP run on openwrt device.

image
image2728×1488 178 KB

The problem is : when using LTE doggle (LAN cable removed), AP not provide IP to user. Mobile screen show message 'Obtaining IP address....' forever.
How can i modify config to share internet from LTE to user?

Thank you

This is my configurations:

  1. /etc/config/network
config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'fdb2:02d3:2f19::/48'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0'

config interface 'lan'
        option device 'br-lan'
        option proto 'dhcp'
        option ip6assign '60'

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '0'

config interface '4G'
        option apn 'v-internet'
        option modes 'lte'
        option device 'eth1'
        option proto 'dhcp'
        option auto '1'


config interface 'wan'
        option device 'wlan0'
        option proto 'dhcp'
  1. /etc/config/wireless
config wifi-device 'radio0'
        option type 'mac80211'
        option path 'platform/10300000.wmac'
        option channel '1'
        option band '2g'
        option htmode 'HT20'
        option disabled '0'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'wan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'none'
  1. /etc/config/dhcp
config dnsmasq
        option domainneeded '1'
        option boguspriv '1'
        option filterwin2k '0'
        option localise_queries '1'
        option rebind_protection '1'
        option rebind_localhost '1'
        option local '/lan/'
        option domain 'lan'
        option expandhosts '1'
        option nonegcache '0'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
        option nonwildcard '1'
        option localservice '1'
        option ednspacket_max '1232'

config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'
        option dhcpv6 'server'
        option ra 'server'
        option ra_slaac '1'
        list ra_flags 'managed-config'
        list ra_flags 'other-config'
        option ignore '0'

config dhcp 'wan'
        option interface 'wan'
        option ignore '0'

config odhcpd 'odhcpd'
        option maindhcp '0'
        option leasefile '/tmp/hosts/odhcpd'
        option leasetrigger '/usr/sbin/odhcpd-update'
        option loglevel '4'
  1. /etc/config/firewall
config defaults
        option syn_flood '1'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'REJECT'

config zone
        option name 'lan'
        list network 'lan'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'ACCEPT'

config zone
        option name 'wan'
        list network 'wan 4G'
        list network 'wan6'
        option output 'ACCEPT'
        option forward 'REJECT'
        option masq '1'
        option mtu_fix '1'
        option input 'ACCEPT'

config forwarding
        option src 'lan'
        option dest 'wan'

config rule
        option name 'Allow-DHCP-Renew'
        option src 'wan'
        option proto 'udp'
        option dest_port '68'
        option target 'ACCEPT'
        option family 'ipv4'

config rule
        option name 'Allow-Ping'
        option src 'wan'
        option proto 'icmp'
        option icmp_type 'echo-request'
        option family 'ipv4'
        option target 'ACCEPT'

config rule
        option name 'Allow-IGMP'
        option src 'wan'
        option proto 'igmp'
        option family 'ipv4'
        option target 'ACCEPT'

config rule
        option name 'Allow-DHCPv6'
        option src 'wan'
        option proto 'udp'
        option src_ip 'fc00::/6'
        option dest_ip 'fc00::/6'
        option dest_port '546'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-MLD'
        option src 'wan'
        option proto 'icmp'
        option src_ip 'fe80::/10'
        list icmp_type '130/0'
        list icmp_type '131/0'
        list icmp_type '132/0'
        list icmp_type '143/0'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Input'
        option src 'wan'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        list icmp_type 'router-solicitation'
        list icmp_type 'neighbour-solicitation'
        list icmp_type 'router-advertisement'
        list icmp_type 'neighbour-advertisement'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Forward'
        option src 'wan'
        option dest '*'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-IPSec-ESP'
        option src 'wan'
        option dest 'lan'
        option proto 'esp'
        option target 'ACCEPT'

config rule
        option name 'Allow-ISAKMP'
        option src 'wan'
        option dest 'lan'
        option dest_port '500'
        option proto 'udp'
        option target 'ACCEPT'

config rule
        option name 'Support-UDP-Traceroute'
        option src 'wan'
        option dest_port '33434:33689'
        option proto 'udp'
        option family 'ipv4'
        option target 'REJECT'
        option enabled 'false'

config include
        option path '/etc/firewall.user'
  1. ifconfig
br-lan    Link encap:Ethernet  HWaddr 9C:65:F9:3E:E3:84  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

eth0      Link encap:Ethernet  HWaddr 9C:65:F9:3E:E3:84  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:5 

eth1      Link encap:Ethernet  HWaddr AC:7F:60:AF:F7:3B  
          inet addr:192.168.0.100  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::ae7f:60ff:feaf:f73b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:255 errors:0 dropped:0 overruns:0 frame:0
          TX packets:834 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:33544 (32.7 KiB)  TX bytes:174632 (170.5 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:348 errors:0 dropped:0 overruns:0 frame:0
          TX packets:348 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:47764 (46.6 KiB)  TX bytes:47764 (46.6 KiB)

wlan0     Link encap:Ethernet  HWaddr 06:60:F3:0E:91:27  
          inet6 addr: fe80::460:f3ff:fe0e:9127/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:13 errors:0 dropped:0 overruns:0 frame:0
          TX packets:155 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2432 (2.3 KiB)  TX bytes:51236 (50.0 KiB)
2

You only need these changes:

  • Add the 4G network.
  • Add the 4G network to the wan zone in the firewall configuration

Your wireless network should be on the LAN zone (default)

3

Dear @laigo

I'm newbie and dummy, could you please give me an example configuration file?

Thank you.

4

Is your LTE dongle actually eth1? That feels like actually what the default wan should be.

5

Hi @laigo

Yes, LTE is ETH1.

I was add this configuration to firewall, but still cannot get IP

config zone
    option name 'wan'
        list network 'wan'
        list network 'wan6'
        list network '4G'
        option output 'ACCEPT'
        option forward 'REJECT'
        option masq '1'
        option mtu_fix '1'
        option input 'ACCEPT'
6

Restore this to the default wan interface configuration.

config interface 'wan'
        option device 'wlan0'
        option proto 'dhcp'

and change this back to lan.

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'wan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'none'
7

Dear @laingo

Following your comment, i modified configuration file, but problems still existed.
Note : removed LAN cable, i will use only LTE dongle for simpler configuration.

  1. /etc/config/network
config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'fdfa:58f1:fc48::/48'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0'

config interface 'lan'
        option device 'br-lan'
        option proto 'dhcp'
        option ip6assign '60'
        option dns '8.8.8.8 8.8.4.4'

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '0'

config interface '4G'
        option apn 'v-internet'
        option modes 'lte'
        option device 'eth1'
        option auto '1'
        option proto 'dhcp'

config interface 'wan'
        option proto 'dhcp'
        option device 'eth1'
        option auto '1'
  1. /etc/config/wireless
config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'none'
  1. /etc/config/firewall
config defaults
        option syn_flood '1'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'REJECT'

config zone
        option name 'lan'
        list network 'lan'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'ACCEPT'

config zone
        option name 'wan'
        list network 'wan'
        list network 'wan6'
        list network '4G'
        option output 'ACCEPT'
        option forward 'REJECT'
        option masq '1'
        option mtu_fix '1'
        option input 'ACCEPT'

config forwarding
        option src 'lan'
        option dest 'wan'

config rule
        option name 'Allow-DHCP-Renew'
        option src 'wan'
        option proto 'udp'
        option dest_port '68'
        option target 'ACCEPT'
        option family 'ipv4'

config rule
        option name 'Allow-Ping'
        option src 'wan'
        option proto 'icmp'
        option icmp_type 'echo-request'
        option family 'ipv4'
        option target 'ACCEPT'

config rule
        option name 'Allow-IGMP'
        option src 'wan'
        option proto 'igmp'
        option family 'ipv4'
        option target 'ACCEPT'

config rule
        option name 'Allow-DHCPv6'
        option src 'wan'
        option proto 'udp'
        option src_ip 'fc00::/6'
        option dest_ip 'fc00::/6'
        option dest_port '546'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-MLD'
        option src 'wan'
        option proto 'icmp'
        option src_ip 'fe80::/10'
        list icmp_type '130/0'
        list icmp_type '131/0'
        list icmp_type '132/0'
        list icmp_type '143/0'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Input'
        option src 'wan'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        list icmp_type 'router-solicitation'
        list icmp_type 'neighbour-solicitation'
        list icmp_type 'router-advertisement'
        list icmp_type 'neighbour-advertisement'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Forward'
        option src 'wan'
        option dest '*'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-IPSec-ESP'
        option src 'wan'
        option dest 'lan'
        option proto 'esp'
        option target 'ACCEPT'

config rule
        option name 'Allow-ISAKMP'
        option src 'wan'
        option dest 'lan'
        option dest_port '500'
        option proto 'udp'
        option target 'ACCEPT'

config rule
        option name 'Support-UDP-Traceroute'
        option src 'wan'
        option dest_port '33434:33689'
        option proto 'udp'
        option family 'ipv4'
        option target 'REJECT'
        option enabled 'false'

config include
        option path '/etc/firewall.user'
  1. /etc/config/dhcp
config dnsmasq
        option domainneeded '1'
        option boguspriv '1'
        option filterwin2k '0'
        option localise_queries '1'
        option rebind_protection '1'
        option rebind_localhost '1'
        option local '/lan/'
        option domain 'lan'
        option expandhosts '1'
        option nonegcache '0'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
        option nonwildcard '1'
        option localservice '1'
        option ednspacket_max '1232'

config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'
        option dhcpv6 'server'
        option ra 'server'
        option ra_slaac '1'
        list ra_flags 'managed-config'
        list ra_flags 'other-config'
        option ignore '1'

config dhcp 'wan'
        option interface 'wan'
        option ignore '1'

config odhcpd 'odhcpd'
        option maindhcp '0'
        option leasefile '/tmp/hosts/odhcpd'
        option leasetrigger '/usr/sbin/odhcpd-update'
        option loglevel '4'
8

You should setup the OpenWrt device as a router or move the DHCP server to it. Currently you have the IPs given by the "Home" router, so it doesn't have a routing table entry to route back to the OpenWrt's modem. Even if you have the routing in place - if you remove the cable it won't work and you will have no DHCP. Moreover the DHCP is not expired over the client devices and won't be renewed, even the DHCP server of the OpenWrt server gets restarted.
You must configure some static IP to the LAN:

config interface 'lan'
option proto 'static'
option netmask '255.255.255.0' #-> Change to current netmsk
option ipaddr '192.168.1.2' #-> This could be the current IP of the router
option gateway '192.168.1.1' #-> This is the IP of the "Home Router"
option dns '192.168.1.1' #-> This is the IP of the "Home Router"
option metric '10' #-> The traffic will be routed over the interface with less metric.

You may check IP and the gateway with the "ifconfig" and "route" commands.

You must disable the DHCP server over the "Home" router.

Running /etc/init.d/network restart should restart dnsmasq as well.

9

Switch this to 0 in the dhcp config for lan.
If you still cannot connect, share your routing table with and without the cable connected.

ip route

10

Why not simply follow https://openwrt.org/docs/guide-user/network/wifi/dumbap ?

11

This will not work, but make it worse since both devices may reply to the DHCP request.

Because huybk213 is trying to offload the NAT to the "Home" router, but doing routing and NAT over the OpenWrt router for the LTE modem. It must also work with the cable unplugged.

The latest configuration looks almost ok, except the wrong placement of the DHCP server.