Bad Argument `lo'

Bad Argument `lo'

[Markus Feldmann]

Hi All,

i using iptables (version 1.4.14) on a LMDE(Debian like) with kernel 
3.5.3. Some days before i watched my logs after several weeks again. :-) 
And i spotted the error message:

Bad argument `lo'

So i searched at google to get a solution and i got one. Some user told 
to put the <lo> into ticks, like this

'!lo'

My iptables-rules regarding on this problem were looking so,

...
iptables -A INPUT -i ! lo -s 127.0.0.1 -j DROP
...

and i changed this line to,

...
iptables -A INPUT -i '!lo' -s 127.0.0.1 -j DROP
...

Now i am not sure, if this works correctly. <iptables -L> shows me the 
device "!lo",

######################################################################
Chain INPUT (policy DROP 0 packets, 0 bytes)
  pkts bytes target     prot opt in     out     source 
destination
     0     0 LOG        all  --  !lo    any     localhost 
anywhere             limit: avg 3/sec burst 5 LOG level warning prefix 
"Loopback gespooft: "
     0     0 DROP       all  --  !lo    any     localhost 
anywhere
######################################################################

but i am not sure if this works correctly. Does somebody knows if this 
trick works correctly?

regards Markus

Bad Argument `lo'

[Markus Feldmann]

Hi All,

i using iptables (version 1.4.14) on a LMDE(Debian like) with kernel 
3.5.3. Some days before i watched my logs after several weeks again. :-) 
And i spotted the error message:

Bad argument `lo'

So i searched at google to get a solution and i got one. Some user told 
to put the <lo> into ticks, like this

'!lo'

My iptables-rules regarding on this problem were looking so,

...
iptables -A INPUT -i ! lo -s 127.0.0.1 -j DROP
...

and i changed this line to,

...
iptables -A INPUT -i '!lo' -s 127.0.0.1 -j DROP
...

Now i am not sure, if this works correctly. <iptables -L> shows me the 
device "!lo",

######################################################################
Chain INPUT (policy DROP 0 packets, 0 bytes)
  pkts bytes target     prot opt in     out     source destination
     0     0 LOG        all  --  !lo    any     localhost anywhere 
        limit: avg 3/sec burst 5 LOG level warning prefix "Loopback 
gespooft: "
     0     0 DROP       all  --  !lo    any     localhost anywhere
######################################################################

but i am not sure if this works correctly. Does somebody knows if this 
trick works correctly?

regards Markus

Re: Bad Argument `lo'

[Eric Leblond]

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Hi,

Le jeudi 04 octobre 2012 à 21:14 +0200, Markus Feldmann a écrit :
> Hi All,
> 
> i using iptables (version 1.4.14) on a LMDE(Debian like) with kernel 
> 3.5.3. Some days before i watched my logs after several weeks again. :-) 
> And i spotted the error message:
> 
> Bad argument `lo'
> 
> So i searched at google to get a solution and i got one. Some user told 
> to put the <lo> into ticks, like this
> 
> '!lo'

Nope the solution is given in the man page:
   [!] -i, --in-interface name

So you need
	iptables -A INPUT ! -i lo -s 127.0.0.1 -j DROP

BR,
> 
> My iptables-rules regarding on this problem were looking so,
> 
> ...
> iptables -A INPUT -i ! lo -s 127.0.0.1 -j DROP
> ...
> 
> and i changed this line to,
> 
> ...
> iptables -A INPUT -i '!lo' -s 127.0.0.1 -j DROP
> ...
> 
> Now i am not sure, if this works correctly. <iptables -L> shows me the 
> device "!lo",
> 
> ######################################################################
> Chain INPUT (policy DROP 0 packets, 0 bytes)
>   pkts bytes target     prot opt in     out     source destination
>      0     0 LOG        all  --  !lo    any     localhost anywhere 
>         limit: avg 3/sec burst 5 LOG level warning prefix "Loopback 
> gespooft: "
>      0     0 DROP       all  --  !lo    any     localhost anywhere
> ######################################################################
> 
> but i am not sure if this works correctly. Does somebody knows if this 
> trick works correctly?
> 
> regards Markus
> --
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-- 
Eric Leblond 
Blog: http://home.regit.org/ - Portfolio: http://regit.500px.com/

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