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Fine tuning DHCPv6 and Router Advertisments on AVM Fritz!Box
![[de]](/s/countries/de.gif) Shadow Hawkins on Sunday, 01 January 2012 21:56:17
Enabling IPv6 will unconditionally enable a DHCPv6 server on the Fritz!Box. There is no way to disable the server or control the content of the router advertisements (RA) via Web configuration. This is very unfortunate if you already have a DHCPv6 service on a separate server.
For those who have enabled telnet on Fritz!Box there is the possibility to overcome those shortcomings. In ar7.cfg there is a setting "dhcpv6lanmode" that controls the DHCPv6 and RA behaviour. The supported values are:
dhcpv6lanmode_off
dhcpv6lanmode_stateless (default)
dhcpv6lanmode_statefull
dhcpv6lanmode_onlyprefixes
dhcpv6lanmode_off_stateless
dhcpv6lanmode_off_statefull
dhcpv6lanmode_off_stateless is most useful if running a DHCPv6 service on another server as it turns off the DHCPv6 server in the Fritz!Box but leaves the "Other configuration" option in the RA on. dhcpv6lanmode_off_statefull in addition turns on the "Managed address configuration" option in the RA to allow for DHCPv6 server assigned addresses. (The "..._off_..." settings have been tested on a 7390 with 84.05.07beta firmware. The setting is already in the 84.05.05 firmware but has not been verified to work.)
I've put this in the Wiki as well.
Fine tuning DHCPv6 and Router Advertisments on AVM Fritz!Box
Hmmm I have a "FRITZ!Box Fon WLAN 7270 v2" with 54.05.05 configured with "Internet connection via LAN 1" and "Share existing Internet connection in the network (IP client)" which causes it to be a full IP client. DHCP (v4 + v6) is handled by a separate box which also does the RAs and I have not have to change these settings.
The primary reason why I don't use the Fritz!Box as my gateway is the lack of control over the firewall and the subnetting etc, now the other box does all of that the way I like it.
The Fritz!Box thus only sits there playing wifi-bridge and telephone blocker, as that is one function that works really well in that device. (Which reminds me to still try to get it to allow me to talk SIP to the Fritz!Box and that it makes outbound calls over the attached hardline hmmm)
Fine tuning DHCPv6 and Router Advertisments on AVM Fritz!Box
Shadow Hawkins on Sunday, 01 January 2012 23:45:25
The setting I mentioned above is only required/useful if you use the Fritz!Box as an IPv6 router. In the pure client mode it does not make much sense.
But as the SIXXS tunnel works quite nicely for me (as well as IPv4 with an external cable modem) I don't see any reason to have another device adding to my electric power bill :-).
One shortcoming though is that the IPv6 filter on the Fritz!Box does only allow to configure TCP, UDP and ICMPv6 echo requests. Other than for IPv4 ESP and GRE are not supported. Which is a shame as with IPv4 you hardly need ESP because of NAT-T where with IPv6 this would be very useful.
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![[ch]](/s/countries/ch.gif)
on Sunday, 01 January 2012 22:08:51
Posting is only allowed when you are