Unable to obtain IPV6.

[pymumu]

Router Model Affected
Models: RT-AX82U

Firmware Version Affected
388.8_2

Is this bug present in upstream Merlin releases too?
NA

Describe the bug
After setting the IPV6 rules, restarting the router cannot obtain the IPV6 address assigned by the carrier.
After deleting the IPV6 rules or turning off the IPV6 firewall, IPV6 can be successfully obtained.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'IPV6'
2. Select 'Connection type' 'Native', 'Interface' PPP
3. Set IPV6 Firmware Rules:

[Remote IP]: Empty
[Local IP]: ::xxxx:32ff:fe4a:xxxx/::ffff:ffff:ffff:ffff
[Port]: 1118
[Protocol]: udp

4. No IPV6 address obtained

Expected behavior
There is no problem with the official firmware.
Set IP rules and restart the router to quickly obtain the IPV6 address.

Screenshots
admin@RT-AX82U:/tmp/home/root# odhcp6c -R -s /tmp/dhcp6c -N try -c 00030001c87f540ea510 -P 0:ea510 -r23 -r24 ppp0 -e -vvvv

odhcp6c[9068]: (re)starting transaction on ppp0
odhcp6c[9068]: Starting SOLICIT transaction (timeout 4294967295s, max rc 0)

[odhcp6c stuck here]

[gnuton]

Hi!
did you try to run odhcp6c in debug mode (-d -f ) to check what happens?

[pymumu]

The -d option is daemonize, not DEBUG mode.
The DEBUG option is not found in the parameter list.

Invocation options:
        -p <pidfile>    Set pidfile (/var/run/odhcp6c.pid)
        -d              Daemonize
        -e              Write logmessages to stderr
        -v              Increase logging verbosity
        -h              Show this help

[gnuton]

How do you set the rule? What's the config you use?

[pymumu]

The Rule:

Chain FORWARD (policy DROP)
ACCEPT     udp      anywhere             ::xxxx:67ff:fe3b:xxxx/::ffff:ffff:ffff:ffff  state NEW udp dpt:xxxx

Steps to reproduce the behavior:

1. Go to 'IPV6'
2. Select 'Connection type' 'Native', 'Interface' PPP
3. Set IPV6 Firewall Rules:

[Remote IP]: Empty
[Local IP]: ::xxxx:32ff:fe4a:xxxx/::ffff:ffff:ffff:ffff
[Port]: 1118
[Protocol]: udp

I just want to forward the IPV6 request with specific port to an internal host.