[NR7302] DHCP renewal fails on IP pass-through

mbo77
mbo77 Posts: 4  Freshman Member
First Comment
in Mobile Broadband

I'm operating a NR7302 on a Telekom 5G network in pass-through mode. The router is an OpenWRT device.

The interface is set to renew the lease from time to time, but when this happens, the renewal fails and a new lease is requested. This leads to an interruption of appr. 10 seconds.

Here is the tcpdump when a renewal is happening.

NR7302 IP passthrough DHCP renewal.txt

As you can see, the renewal request is denied ("NACK" / "lease not found"), so the router starts a new discovery.

Is this a known issue, or maybe some kind of misconfiguration on my side?

Accepted Solution

  • mbo77
    mbo77 Posts: 4  Freshman Member
    First Comment
    Answer ✓

    OK, got it solved, with only a minimum of mystery left. I had to enable the ARP Proxy, now the renewals are transferred correctly between the router and the APN.

    The only mystery left is the default lease time value with 0. Is it always 24h or derived from the ISP's DHCP server? Given the request above, the latter doesn't seem to be the case.

All Replies

  • PeterUK
    PeterUK Posts: 3,940  Guru Member
    100 Answers 2500 Comments Friend Collector Seventh Anniversary
    edited July 27

    This might be your ISP doing when they change the 10. IP if they change it every so many hours

    IP pass-through is not a true interaction with the ISP gateway instead the NR7302 acks as a proxy 1:1 not NAT so you get the IP you would of got by true interaction with the gateway.

    One of the problems thats posted here is Zyxel lease can be longer then the real lease and so you may lose connection
    https://community.zyxel.com/en/discussion/25880/feature-request-immediate-dhcp-renewal-for-ip-passthrough-mode#latest

    It would be best if Zyxel can relay the lease time the ISP is doing.

  • mbo77
    mbo77 Posts: 4  Freshman Member
    First Comment
    Answer ✓

    OK, got it solved, with only a minimum of mystery left. I had to enable the ARP Proxy, now the renewals are transferred correctly between the router and the APN.

    The only mystery left is the default lease time value with 0. Is it always 24h or derived from the ISP's DHCP server? Given the request above, the latter doesn't seem to be the case.

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