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tobcon
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Posts: 18
Joined: Sun Mar 06, 2022 6:57 pm

IPv6 SLAAC wrong prefix

Fri Dec 27, 2024 11:17 pm

This is my IPv6 config:
[admin@fw-xxx0-0] > /ipv6 export
# 2024-12-27 22:08:31 by RouterOS 7.14.3
# software id = JLI2-LN5C
#
# model = CCR1009-8G-1S-1S+
# serial number = xxx
/ipv6 address
add address=::90 from-pool=fiber6 interface=vlan90
/ipv6 dhcp-client
add add-default-route=yes interface=wan10 pool-name=fiber6 pool-prefix-length=48 request=address,prefix \
    use-peer-dns=no
/ipv6 firewall filter
add action=accept chain=input comment="allow established and related" connection-state=established,related
add action=accept chain=input comment="accept ICMPv6" protocol=icmpv6
add action=accept chain=input comment="defconf: accept UDP traceroute" port=33434-33534 protocol=udp
add action=accept chain=input comment="accept DHCPv6-Client prefix delegation." dst-port=546 protocol=udp \
    src-address=fe80::/16
add action=accept chain=input comment="allow allowed addresses" disabled=yes src-address-list=allowed
add action=drop chain=input
add action=accept chain=forward comment=established,related connection-state=established,related
add action=drop chain=forward comment=invalid connection-state=invalid log=yes log-prefix=ipv6,invalid
add action=accept chain=forward comment=icmpv6 protocol=icmpv6
add action=accept chain=forward comment="local network" in-interface=!wan10
add action=drop chain=forward log-prefix=IPV6
This is what my computer interface gets:
3: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 04:cf:4b:1e:xx:xx brd ff:ff:ff:ff:ff:ff
    altname wlx04cf4b1e412d
    inet 172.16.90.117/24 brd 172.16.90.255 scope global dynamic noprefixroute wlp3s0
       valid_lft 1186sec preferred_lft 1186sec
    inet6 2a02:xxxx:xxxx:0:7e4b:266:xxxx:xxxx/64 scope global dynamic noprefixroute 
       valid_lft 2591866sec preferred_lft 604666sec
    inet6 fe80::17fc:d894:xxxx:xxxx/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
Any idea why it is in :0: instead of :90: as specified in the Mikrotik config?
 
tdw
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Posts: 2084
Joined: Sat May 05, 2018 11:55 am

Re: IPv6 SLAAC wrong prefix

Sat Dec 28, 2024 12:58 am

address=::90 from-pool=fiber6 specifies a local host address of 0000:0000:0000:0090 with a prefix from the pool. There is a longstanding gripe that you can't provide a prefix hint, e.g. ::90:0:0:0:1