DHCP trouble with Kabeldeutschland (Vodafone) - DOCSIS3


have some trouble switching from Fritz.Box to OpenWRT 19.7.6 as DHCP does not work fine with my cable router in bridge mode.

I enabled DOCSIS3 support and normally get an external IP. But sometimes I did not get a successful DHCP request trough and have to restart my cable modem. In the post below I found a remark that DOCSIS3 will deliver IPs in a short time after restart of the modem only. But I never had issues with my Fritz.Box but it matches what I see. Mostly I have to restart the modem if I have to restart the router. If both works fine I see no problems but actually installing some packages I run into that. Is there a way around this problem or is it a must to restart both devices? I also want to stay in bridgemode.


Did you ever resolve this? I think I am running into this on Vodafone in Czechia.

There is a 15 minutes frame after successful connection there could be DHCP requests from the router. It must be of because before the modem will deliver local IPs. But I did not get why it’s different with Fritz Box.

That is only the case with bridge mode.

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FYI: I enabled the "Use broadcast flag" on my Router because I had the same issue with my provider. This resolved the issue for me.