Help with WAN / DHCP troubleshooting

Hello, I'm using openwrt on a Zyxel EX5601-T0 with an SFP GPON STICK LEOX LXT-010S-H. The problem is that I can't get the IP from my WAN in DHCP mode. Here is my network configuration:

config device
        option name 'eth1'
        option macaddr 'xx:xx:xx:xx:xx:xx'

config interface 'wan'
        option device 'eth1'
        option proto 'dhcp'
        option vendorid 'myVendorIDOption'

All seems fine on the GPON side, however, inspecting eth1 with tcpdump, there are a bunch of DHCP requests with no answer. The following is one of them:

04:15:45.371032 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 333)
    0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from aa:aa:aa:aa:aa:aa, length 305, xid 0x68995640, secs 275, Flags [none] (0x0000)
   Client-Ethernet-Address xx:xx:xx:xx:xx:xx
   Vendor-rfc1048 Extensions
     Magic Cookie 0x63825363
     DHCP-Message (53), length 1: Discover
     MSZ (57), length 2: 576
     Parameter-Request (55), length 9:
       Subnet-Mask (1), Default-Gateway (3), Domain-Name-Server (6), Hostname (12)
       Domain-Name (15), BR (28), NTP (42), Classless-Static-Route (121)
       Unknown (212)
     Hostname (12), length 7: "OpenWrt"
     Vendor-Class (60), length 35: "myVendorIDOption"
     END (255), length 0

Can you help me troubleshoot this problem?

If you are not getting a response, there is little we can do. Try to power off the ISP modem for 30 minutes to clear its cache and let it accept DHCP requests from a different MAC address.

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I see. Is there a way to capture ethernet frames inside openwrt?

EDIT: oh, maybe tcpdump can be enough

What does "inside openwrt" mean?

I mean from the openwrt shell.

tcpdump it is.

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Is sending a VendorID an ISP requirement?

With my ISP, it's 2 hours to clear a lease after a device sends a VendorID. In the past, you could call their phone support to clear the lease, they now tell you to wait the 2 hours.

Just curious, if you weren't using the OpenWrt at the time, where/how did you record the packet in your first post?

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Is sending a VendorID an ISP requirement?

Yes, it is

With my ISP, it's 2 hours to clear a lease after a device sends a VendorID. In the past, you could call their phone support to clear the lease, they now tell you to wait the 2 hours.

Already done with no luck

Just curious, if you weren't using the OpenWrt at the time, where/how did you record the packet in your first post?

Those are packets recorded in OpenWrt not in my working environment

Then you can call your ISP to ask them to clear the previous mac address from the modem so the OpenWrt can get an address.

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I spoofed the previous mac address, so opewrt is already presenting with the same.

Okay, then call your ISP to ask why your router is not getting an IP.

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