[B.A.T.M.A.N.] batmand terminates silently

[B.A.T.M.A.N.] batmand terminates silently

[Freifunk Dresden]

Hello Axel,


few weeks agoe I had sometimes the problem that batmand (experimental) exits
silently. Today I found maybe one reason for this.
When you have batman running and insert the iptable rule

iptables -I OUTPUT -o eth1 -j DROP


batmand exits. This also happen for additional interfaces controlled
by batmand.

Maybe it helps you a little.

Regards, Stephan

Re: [B.A.T.M.A.N.] batmand terminates silently

[Axel Neumann]

Hello,

On Dienstag 25 September 2007, Freifunk Dresden wrote:
> Hello Axel,
>
>
> few weeks agoe I had sometimes the problem that batmand (experimental)
> exits silently. Today I found maybe one reason for this.
> When you have batman running and insert the iptable rule
>
> iptables -I OUTPUT -o eth1 -j DROP
>
>
> batmand exits. This also happen for additional interfaces controlled
> by batmand.

Ah sure,
its not a bug, its a feature :-)
Batman checks if packets generated on its behaf are blocked by a firewall and 
exits if this is the case.
The assumption when implementing this was, that usually the firewall is 
configured before batmand is started and not touched later on.

In the assumed case the immediate exit helps to directly indicate the problem 
to the maintainer of the node. Actually debuglevel 3 should report this.

Of course in your fancy setups this might be undesirable and having an option 
to disable this feature is a good idea. Put this on the todo list.

ciao, 
axel

Re: [B.A.T.M.A.N.] batmand terminates silently

[Marek Lindner]

Hi,

> few weeks agoe I had sometimes the problem that batmand (experimental)
> exits silently. Today I found maybe one reason for this.
> When you have batman running and insert the iptable rule
>
> iptables -I OUTPUT -o eth1 -j DROP
>
>
> batmand exits. This also happen for additional interfaces controlled
> by batmand.

actually this is logged to syslog and debug level 4. A "logread -f" on OpenWRT 
systems should show something like that: 

Error - can't send udp packet: Permission denied.
Does your firewall allow outgoing packets on port 4306 ?

Regards,
Marek

Re: [B.A.T.M.A.N.] batmand terminates silently

[Axel Neumann]

Hi Stephan,


you can use rv 687 with
--resist-blocking-send 
which lets daemon survive if firewall blocks outgoing OGMs

regards
axel


> > few weeks agoe I had sometimes the problem that batmand (experimental)
> > exits silently. Today I found maybe one reason for this.
> > When you have batman running and insert the iptable rule
> >
> > iptables -I OUTPUT -o eth1 -j DROP
> >
> >
> > batmand exits. This also happen for additional interfaces controlled
> > by batmand.
>
> Ah sure,
> its not a bug, its a feature :-)
> Batman checks if packets generated on its behaf are blocked by a firewall
> and exits if this is the case.
> The assumption when implementing this was, that usually the firewall is
> configured before batmand is started and not touched later on.
>
> In the assumed case the immediate exit helps to directly indicate the
> problem to the maintainer of the node. Actually debuglevel 3 should report
> this.
>
> Of course in your fancy setups this might be undesirable and having an
> option to disable this feature is a good idea. Put this on the todo list.
>
> ciao,
> axel