Radvd missing

[Danifunker]

New asuswrt-Merlin user here, but longtime dd-wrt user... Just setup my new rt-ac87r with the latest asuswrt-Merlin firmware, and I have been having issues with IPv6. My IPv4 dhcp server is a Windows pc, so I try not to run dhcp services from the router. In the initial configuration I tried, I disabled IPv6 dhcp but enabled "router advertisement", my clients got neither an IPv6 address nor the router address. In my current configuration, I enable dhcpv6 and router advertisement, but I don't see radvd anywhere on the router, as well it's not a running process. How can I get it installed? I need it to advertise the router IP properly in order for my clients to connect properly.

If I can't get this sorted out by the weekend I might just have to go back to dd-wrt. Thanks!

 

[RMerlin]

New asuswrt-Merlin user here, but longtime dd-wrt user... Just setup my new rt-ac87r with the latest asuswrt-Merlin firmware, and I have been having issues with IPv6. My IPv4 dhcp server is a Windows pc, so I try not to run dhcp services from the router. In the initial configuration I tried, I disabled IPv6 dhcp but enabled "router advertisement", my clients got neither an IPv6 address nor the router address. In my current configuration, I enable dhcpv6 and router advertisement, but I don't see radvd anywhere on the router, as well it's not a running process. How can I get it installed? I need it to advertise the router IP properly in order for my clients to connect properly.

If I can't get this sorted out by the weekend I might just have to go back to dd-wrt. Thanks!

Asuswrt no longer uses radvd, router advertisement is handled by dnsmasq now.

 

[Danifunker]

Thanks for the quick response.

I have the following options in my dnsmasq.conf (I did not modify this file manually) and dnsmasq.conf.add (this is the file I created)

pid-file=/var/run/dnsmasq.pid
user=nobody
bind-dynamic
interface=br0
interface=ppp1*
no-dhcp-interface=ppp1*
resolv-file=/tmp/resolv.conf
servers-file=/tmp/resolv.dnsmasq
no-poll
no-negcache
cache-size=1500
min-port=4096
dhcp-option=lan,option6:23,[::]
no-dhcp-interface=br0
quiet-dhcp
quiet-dhcp6

dnsmasq.conf.add
enable-ra
dhcp-range=2001:XXX:XX:XXX::, ra-only
log-dhcp

when I check the syslog it says that it's running

Apr 7 22:14:06 dnsmasq[583]: exiting on receipt of SIGTERM
Apr 7 22:14:15 dnsmasq[1288]: started, version 2.73test6 cachesize 1500
Apr 7 22:14:15 dnsmasq[1288]: warning: interface ppp1* does not currently exist
Apr 7 22:14:15 dnsmasq[1288]: asynchronous logging enabled, queue limit is 5 messages
Apr 7 22:14:15 dnsmasq-dhcp[1288]: DHCPv6 stateless on br0
Apr 7 22:14:15 dnsmasq-dhcp[1288]: router advertisement on br0
Apr 7 22:14:15 dnsmasq-dhcp[1288]: DHCPv6 stateless on 2001:XXX:XX:XXX::, constructed for br0
Apr 7 22:14:15 dnsmasq-dhcp[1288]: router advertisement on 2001:XXX:XX:XXX::, constructed for br0
Apr 7 22:14:15 dnsmasq-dhcp[1288]: IPv6 router advertisement enabled
Apr 7 22:14:15 dnsmasq[1288]: read /etc/hosts - 6 addresses
Apr 7 22:14:15 dnsmasq[1288]: using nameserver 2001:XXX:XX:XXX::c#53
Apr 7 22:14:15 dnsmasq[1288]: using nameserver 2001:XXX:XX:XXX::b#53
Apr 7 22:14:15 dnsmasq[1288]: using nameserver 209.197.128.5#53 for domain local
Apr 7 22:14:15 dnsmasq[1288]: using nameserver 209.197.128.2#53 for domain local
Apr 7 22:14:15 dnsmasq[1288]: using nameserver 209.197.128.2#53
Apr 7 22:14:15 dnsmasq[1288]: using nameserver 209.197.128.5#53
Apr 7 22:14:16 dnsmasq[1288]: read /etc/hosts - 6 addresses
Apr 7 22:14:16 dnsmasq[1288]: using nameserver 2001:XXX:XX:XXX::c#53
Apr 7 22:14:16 dnsmasq[1288]: using nameserver 2001:XXX:XX:XXX::b#53
Apr 7 22:14:20 dnsmasq[1288]: read /etc/hosts - 6 addresses
Apr 7 22:14:20 dnsmasq[1288]: using nameserver 2001:XXX:XX:XXX::c#53
Apr 7 22:14:20 dnsmasq[1288]: using nameserver 2001:XXX:XX:XXX::b#53
Apr 7 22:14:20 dnsmasq[1288]: using nameserver 209.197.128.5#53 for domain local
Apr 7 22:14:20 dnsmasq[1288]: using nameserver 209.197.128.2#53 for domain local
Apr 7 22:14:20 dnsmasq[1288]: using nameserver 209.197.128.2#53
Apr 7 22:14:20 dnsmasq[1288]: using nameserver 209.197.128.5#53
Apr 7 22:14:22 dnsmasq-dhcp[1288]: DHCPSOLICIT(br0) 00:01:00:01:19:31:e4:f3:70:54:d2:90:2f:fc
Apr 7 22:14:24 dnsmasq-dhcp[1288]: DHCPCONFIRM(br0) 00:01:00:01:19:31:e9:54:00:15:5d:fe:03:0b
Apr 7 22:14:24 dnsmasq-dhcp[1288]: DHCPCONFIRM(br0) 00:01:00:01:1b:c9:da:f0:00:15:5d:fe:03:01
Apr 7 22:14:24 dnsmasq-dhcp[1288]: DHCPCONFIRM(br0) 00:01:00:01:1b:bc:50:3d:00:15:5d:fe:03:1e
Apr 7 22:14:24 dnsmasq-dhcp[1288]: DHCPCONFIRM(br0) 00:01:00:01:19:f7:41:e3:00:15:5d:fe:03:16

 

[mstombs]

The ppp error also appears on an N66, not a fatal error so asus not bothered to fix it and not add those lines to the conf when not needed

 

[RMerlin]

The ppp error also appears on an N66, not a fatal error so asus not bothered to fix it and not add those lines to the conf when not needed

As the entry says, it's not an error, it's just a warning. dnsmasq is told to listen to ppp interfaces in case you get a PPTP client connecting to your router's PPTP server. It would be a bit silly to restart the whole dnsmasq service every time a pptp client connects, so dnsmasq is told to listen to all ppp* interfaces that might come up later on.

That change was already done by me initially if I remember.

 

[mstombs]

Thanks for clarifying - but if your router is not configured as a pptp server? Personally I use your great firmwares option to use custom conf file, so just commented those lines out, but must manually update if a config change needed such a feature.

 

[Danifunker]

Okay, either way about the PPP error (it is just a warning, I don't care)... Could it be because dhcp is disabled on br0 that it's not serving the router advertisements?

What's another way to disable dhcp but allow router advertising to work?

Also, how can I restart the dnsmasq daemon?

 

[Danifunker]

Update: I found this thread http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2015q1/009109.html

Looks like it's what I'm thinking... So I need to find a way to stop DHCP while allowing the router advertising... Unless there is a way I can bring back radvd

 

[Danifunker]

OK, I got it "working", but I'm still getting a stateless address in this configuration, everything is working together for the most part.

I did it by creating a replacement dnsmasq.conf file in /jffs/configs.
Here is my config:

pid-file=/var/run/dnsmasq.pid
user=nobody
bind-dynamic
interface=br0
resolv-file=/tmp/resolv.conf
servers-file=/tmp/resolv.dnsmasq
no-poll
no-negcache
cache-size=1500
min-port=4096
quiet-dhcp
quiet-dhcp6
enable-ra
dhcp-range=2001:XXX:XX:XXX::, ra-only

Effectively, I removed the following options

dhcp-option=lan,option6:23,[::]
no-dhcp-interface=br0

then added

dhcp-range=2001:XXX:XX:XXX::, ra-only

Now my clients get a DHCP from the router (I believe this is a stateless address), and a stateful address (from my server), as well as the router advertising (which interestingly is actually a local address), and the DNS servers from my server.

Hope this can help someone else... Also I hope Merlin can put together some other changes to actually get this going without my complete hack-ness.

 

[RMerlin]

One way for you to make this more "future-proof" would be to use a postconf script to remove the two lines, then appened the new one, rather than completely replacing the whole config file. That way, if a future firmware update (or a config change) needs to change other parts of the config file, you will still have the updated version.

 

[Danifunker]

One way for you to make this more "future-proof" would be to use a postconf script to remove the two lines, then appened the new one, rather than completely replacing the whole config file. That way, if a future firmware update (or a config change) needs to change other parts of the config file, you will still have the updated version.

Yes, I saw that as an option, but I was afraid when you mentioned in the documentation that you could brick your device requiring a factory reset if there are any errors in the code... Is there any way to test this before a reboot?

 

[RMerlin]

Yes, I saw that as an option, but I was afraid when you mentioned in the documentation that you could brick your device requiring a factory reset if there are any errors in the code... Is there any way to test this before a reboot?

After applying your changes, restart the dnsmasq service over SSH:

service restart_dnsmasq

Then make sure dnsmasq starts normally and works properly.

It's highly unlikely that a misconfigured dnsmasq would brick your router however, it would simply fail to provide name resolution in your particular case. You just need to make sure that nothing in your postconf script will keep the script hanging, since it's not run as a spawned process. When using pc_replace/pc_append calls this is safe.


If you wanted to be 100% safe, make a backup of your router configuration. In case of a disaster, you can do a factory default reset, configure just the basic (password, wifi, WAN), connect through SSH to remove the config file, then restore your saved configuration. The jffs content is not included in the config backup.

 

[mstombs]

... future firmware update...

NB you must save anything on jffs somewhere else, because jffs is lost on a firmware update that is bigger than previous one (jffs fewer erase blocks) BTDTGTTS!

You can test changes to dnsmasq.conf safely by editing the ram disk version in /etc and manually stopping/restarting dnsmasq with the same command line as the firmware (observed using ps).