DHCP requests from wan to lan

Hello, i have OverTheBox device based on OpenWRT and it has 2 DSL routers and 1 5G router attached so tcp multipath aggregaction is done through a tunnel.

The device have DHCP server on br-lan.
I would like to use the routers WiFi so wifi clients could use the internet access.

What is the proper firewall configuration? Currently the WiFi clients do not receive DHCP reply. I tried with tcpdump :

 tcpdump -i eth0.3 -n port 67 and port 68
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0.3, link-type EN10MB (Ethernet), capture size 262144 bytes

17:34:20.389488 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4c:eb:bd:11:a1:bf, length 300
17:34:25.169231 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4c:eb:bd:11:a1:bf, length 300
^C
2 packets captured
2 packets received by filter
0 packets dropped by kernel

But no requests on br-lan:

tcpdump -i br-lan -n port 67 and port 68
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on br-lan, link-type EN10MB (Ethernet), capture size 262144 bytes
^C
0 packets captured
1 packet received by filter
0 packets dropped by kernel

What is the output of

ubus call system board
1 Like

This?

It is not supported by mainstream OpenWRT, but if you are into it with screwdriver and serial adapter....

{
        "kernel": "4.14.74",
        "hostname": "OverTheBox",
        "system": "Intel(R) Atom(TM) x5-Z8350  CPU @ 1.44GHz",
        "model": "OVH SAS OverTheBox V2B",
        "board_name": "ovh-sas-overthebox-v2b",
        "release": {
                "distribution": "OverTheBox",
                "version": "v3.10",
                "revision": "r7345-23a948e726",
                "target": "x86\/64",
                "description": "OverTheBox v3.10 v0.6.33"
        }
}

@brada4 The firewall settings look same as my R7800 OpenWRT so i thought someone could help here.

Judging from kernel version it is iptables firewall3. Should be no issue on LAN side with DHCP propagation at all.
Please check presence of fw4 command and nft which should indicate opposite if present.

This most certainly is not OpenWrt...

You need to reach out to the people who maintain that firmware. Alternatively, you can install genuine OpenWrt which of course supports x86/64.

1 Like

What happens on WAN side is not related to OpenWRT, it is some OVH MPTCP quackery we cant help with at all.

You have to do capture on the disk (/tmp in openwrt) and examine with wireshark to confirm source/destination MAC addresses.