dhclient -P -6 ppp0 does not receive dhcp-server responses

[Udo van den Heuvel]

Hello,

I found something weird.
I was playing around with the IPv6 side of the ethernet interface that 
is the connection to the vdsl modem, and thus carries the PPPoE 
connection, etc.
I removed IPv6 from the ethernet interface and also from the vlan 
interface over this ethernet.
After restarting pppd (?) I suddenly received responses to dhclient's 
prefix requests. (as this sequence (re)starts dhclient and then radvd)

So yes, a bit hairy but I think i got a solution now.
I will close the bug with redhat.
Thank you for thinking about this issue.

Kind regards,
Udo


On 19-05-2021 16:00, Udo van den Heuvel wrote:
> Hello,
> 
> We run fedora 34 on our boxes.
> Dhclient stopped receiving responses from dhcp-server.
> Dhclient only logs XMT steps.
> This happens even with the (ipv6) firewall disabled.
> Tcpdump shows the responses arriving.
> Because of this I created bug 
> https://bugzilla.redhat.com/show_bug.cgi?id=1956209.
> 
> How can I investigate this issue further and fix it?
> 
> Kind regards,
> Udo
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