[B.A.T.M.A.N.] Problem with gateway-dhcp

[B.A.T.M.A.N.] Problem with gateway-dhcp

[Tobias Gieseke]

Hi there,

I'm using batmand 0.3 rv1057 on six Buffalo WHR-HP-G54 with WhiteRussian 
0.9 Open-WRT. The mesh works fine, even the vis-server does its job. But 
I'm having some Problems with the Gateway:

One of the routers is connected to a LAN with internet access via 
WAN-Port and should act as a gateway for the mesh. When the 
Gateway-Router is started interface gate0 is up and runnig but always 
has the Adress 169.254.0.0. The clients recognize the gateway (entry in 
debugmode 2) but can't get a connection to the internet or the standard 
gateway of the LAN. Clients get IP-adress 169.254.0.x (x starting at 1) 
for their gate0 interface and the gateway is aware of that.

For example (can't remember the exact messages but this was about their 
content):
Message on Gateway, Debugmode3:
"Gateway assigned IP adress 169.254.0.1 to client 192.168.100.2"
Message on Client, Debugmode3:
"Got IP adress 169.254.0.1 from Gateway 192.168.100.1"

According to the batman manual the gateway should act as "a tiny DHCP 
server" but as I always get these 169. adresses I assume it isn't 
running properly. I did not touch the firewall or the iptables because I 
don't know anything about it. There might be some entries which would 
solve the problem, but I could not find those in the manual or the 
mailing-list archive.

As I've found a lot of Debug outputs where the Gateway-DHCP was running, 
I'm sure someone can help me out with that little problem.


wireless greetings,

Tobi

Re: [B.A.T.M.A.N.] Problem with gateway-dhcp

[Marek Lindner]

Hi,

> For example (can't remember the exact messages but this was about their
> content):
> Message on Gateway, Debugmode3:
> "Gateway assigned IP adress 169.254.0.1 to client 192.168.100.2"
> Message on Client, Debugmode3:
> "Got IP adress 169.254.0.1 from Gateway 192.168.100.1"

so far, everything as expected. 


> According to the batman manual the gateway should act as "a tiny DHCP
> server" but as I always get these 169. adresses I assume it isn't
> running properly. I did not touch the firewall or the iptables because I
> don't know anything about it. There might be some entries which would
> solve the problem, but I could not find those in the manual or the
> mailing-list archive.

Batman has its internal DHCP server for the gateway tunneling via the gate0 
interfaces. This address space was chosen to avoid configuration as it should 
not be in use. 

You could try to ping the gateway via the virtual address (169.254.0.0) to 
check whether the tunnel connection works or not. If you run into a timeout 
you should disable the firewall on the gateway. Ping again to feel the 
difference.  ;-)

May be you are lacking the the masquerading rules on gate0. Issue:
iptables -t nat -I POSTROUTING -o gate0 -j MASQUERADE
on the client and on the gateway.

Regards,
Marek

Re: [B.A.T.M.A.N.] Problem with gateway-dhcp

[Tobias Gieseke]

Hi,

thanks for the quick answer. But the iptable command didn't make any 
difference.

I'm able to ping the Gateway (169.254.0.0) from the Client (169.254.0.1) 
but I can not ping any futher i.e. to the LAN. Which leads me to the 
assumption that it is a kind of routing problem in my gateway router.
Here are some facts

-    I'm able to get a connection to the internet (from the client) 
without batman by having an ad-hoc connection        to       the gateway.
-    With batman running I can reach the WAN-Interface (192.168.208.x) 
of the gateway from the client.
-    I can not reach the default-gateway of the LAN (192.168.208.251) 
from the client, but of course from the           gateway.
-    I left the default-gateways in the X-WRT webif of the client (WiFi 
and LAN) blank.

I'll try illustrating the network

LAN                        GW                                  Client   
.208.251----ETH---.208.x
                                .222.1-----WLAN-------222.2
                       169.254.0.0--------TUN------169.254.0.1

I'll have to mention that the LAN is quite big. I had to change the IPs 
for the mesh because someone told the 192.168.100.0 net already exists 
in the LAN (whops!).

Here are some question which will help you start your answer to this 
post ;-)

-Do I have to start the batmand with the WAN-Interface (vlan1)? Meaning: 
batmand -g 10mbit eth1 vlan1
-Do I have to announce the 192.168.208.0/24 net  with batman? (I guess not)
-Do I have to set the DNS-Server manualy or is the gateway acting as DNS

I'm sorry this turns out to be more a routing problem than a batman/mesh 
problem. Hope you help me anyway.

Regards,

Tobi

Re: [B.A.T.M.A.N.] Problem with gateway-dhcp

[Marek Lindner]

On Wednesday 15 October 2008 21:26:01 Tobias Gieseke wrote:
> -Do I have to start the batmand with the WAN-Interface (vlan1)? Meaning:
> batmand -g 10mbit eth1 vlan1

No, that is unnecessary. Whenever the batman gateway receives packets for the 
internet it simply adds them to the routing queue. The kernel itself will 
handle further routing.


> -Do I have to announce the 192.168.208.0/24 net  with batman? (I guess not)

Not really unless you want to get a connection to a distinct node other than 
the internet gateway. Remember: you also need a route back if you do so.


> -Do I have to set the DNS-Server manualy or is the gateway acting as DNS

DNS handling is not part of batman. You need to set appropriate DNS entries on 
the clients.


> I'm sorry this turns out to be more a routing problem than a batman/mesh
> problem. Hope you help me anyway.

Sure, no problem. Let us know whether it solves your problem or not.

Regards,
Marek

Re: [B.A.T.M.A.N.] Problem with gateway-dhcp

[Tobias Gieseke]

Hi again,

it is still not running :-( but I was able to specify the problem in 
more detail.
First a short summary of what the problem is:
I got one client connected to a gateway over batman-mesh. Tunnel (gate0) 
is established an has assigned correct IP-Adresses. Problem: I am able 
to ping the gateways WAN-Interface, but I am not able to ping the 
Standard-Gateway of the WAN. The ping to the WAN-Gateway is not leaving 
the WAN-Interface of the gateway (I sniffed that with Wireshark).

Strange: When I'm setting up the Network without Batman (setting a fixed 
gateway on the client) I can ping the Gateway in the WAN. As soon as I 
start the batmand with -g on the Mesh-Gateway the ping stops. Besides, 
the ping does not end up in an error-message it just doesn't answer.

In my last test I "replaced" the WAN (which was actually our 
company-LAN) with another SoHO-Router. So the WAN is now represented by 
this Router. I did this to aviod complications with already assigned 
networks.

Still a routing problem, but any kind of help would be nice.
Thanks!

Tobi

Re: [B.A.T.M.A.N.] Problem with gateway-dhcp

[Marek Lindner]

On Friday 17 October 2008 20:37:10 Tobias Gieseke wrote:
> Strange: When I'm setting up the Network without Batman (setting a fixed
> gateway on the client) I can ping the Gateway in the WAN. As soon as I
> start the batmand with -g on the Mesh-Gateway the ping stops. Besides,
> the ping does not end up in an error-message it just doesn't answer.

It sounds like your ping is going in the right direction but there is no route 
back (the host that wants to send an answer has no routing information to 
route the packet back to its origin). Usually, you can solve that by adding 
routes at the other end or via NAT. 

Its rather difficult to help you that way. I suggest you join our IRC channel on 
irc.freenode.org. You will find us in the #batman channel. There we can debug 
your problems interactively.  :-)

Regards,
Marek