Okay, IPFire is requesting a dhcp lease and there is no reply whatsoever.
In the /var/ipfire/dhcpc/dhcpcd.conf it mentions that some non-RFC compliant DHCP servers do not reply with duid set and that clientid should then be uncommented and duid commented out.
# Use the hardware address of the interface for the Client ID.
#clientid
# or
# Use the same DUID + IAID as set in DHCPv6 for DHCPv4 ClientID as per RFC4361.
# Some non-RFC compliant DHCP servers do not reply with this set.
# In this case, comment out duid and enable clientid above.
duid
I would give that a try and then release and rebind the red interface.
dhcpcd -k red0 ( release interface red0 )
dhcpcd -n red0 ( rebind interface red0 )
If having clientid enabled doesn’t help then you could try with both duid and clientid commented out. The previous version of dhcpcd.conf did not have the duid option and the clientid was present but commented out.
If neither of those work then compare the current dhcpcd.conf file with the previous version and try commenting out in turn any options that are new in the current version. Your ISP must be handling one of these options incorrectly and not replying.
Here is a thread of a case that had the problem that the ISP responded with a NAK response to a request to renew a lease and promptly dropped the ip connection.
https://community.ipfire.org/t/hourly-internet-disconnects-after-upgrade-to-core-159/6139
Commenting out
option rapid_commit
solved his problem.
Any change you make to dhcpcd.conf is backed up with the IPFire backup so will be maintained over Core Updates.
EDIT:
This link shows the commit with the differences in the dhcpcd.conf file made in July 2021. The lines with a + are new lines, the ones with a - at the start have been removed and the ones with neither a + or a - have not been changed. You can see the new entries compared with the previous version.
https://github.com/ipfire/ipfire-2.x/commit/8a59f75a51af312b2fb457c473a3db006472bc45