Re: Re: How to get rid of this firewall error. [Solved]

2010-07-30 Thread Ramasubramanian Ramesh
Thanks for every ones help. I resolved all issues with errors from my 
firewall. Here is a summary


1) My DSL modem/router periodically pings my machine. If I accept then 
it queries more about www server, samba server etc. I do not like these 
requests as I do not know what the modem does with that info. The 
modem/router is given to me by verizon DSL service. So, I shut off any 
incoming packet from that interface that is not already established by 
an in-to-out connection. I was doing this before too, but I was loggin 
in such message. Now I dropped loging it, if it is from my dsl router.


2) I have virtual machines connected with br0 to internal net, and I did 
not do the iptables from br0 to internal net properly and that caused 
nmbd queries from br0 (ie from vms) to rest of the internal net to be 
dropped and loggged. I updated a few rules and the log messages  went away.


3) No my syslog onlyc contains useful messages.

Ramesh


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Re: How to get rid of this firewall error.

2010-07-30 Thread Steven

On Fri, July 30, 2010 07:35, R. Ramesh wrote:
> My bad, I googled icmp_type 8. It seems harmless and required to be
> implemented. So I am going to accept.
> After filtering out this one, I notice another one coming from my own
> firewall and need to figure out who is sending it.
>
> [2731831.967429] IN=eth1 OUT= MAC= SRC=192.168.1.47 DST=192.168.1.255
> LEN=233 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=138 DPT=138
> LEN=213
>
> I think this from my nmbd on the outgoing port. I am going to
> investigate interfaces option in smb.conf. Please tell me if I am on the
> wrong path.
>
Seems more like an incoming packet (the OUT interface is blank), probably
a smb server or windows machine sending its broadcast message (notice the
.255 in the destination IP)

Regards,
Steven

-- 
Rarely do people communicate; they just take turns talking.


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Re: How to get rid of this firewall error.

2010-07-29 Thread R. Ramesh

Ramasubramanian Ramesh wrote:


top posting - iihh ugly ;-p

  well, it's the netfilter code from the kernel instructed by an 
iptables rule, that spits out that message.

most likely this is a message informing you about a blocked packet.
  the question is: who/what set this iptables rule to tell the kernel 
to discard such packets?

my cristal ball is currently somehow foggy, so I can't tell.
maybe you know what firewall frontend you are using?

what to do?
  well - to prohibit logging of those packets in the short term a 
rule like this may do the job:

iptables -I INPUT -i eth1 -s 192.168.1.1 -p icmp --icmp-type 8 -j DROP

for the long term:
learn how to configure your firewall frontend or iptables.

but it's you modem/router right?
  so it might just check if you online. so it could be a 'good 
packet', which you might want to accept. - same thing as above just 
with the ACCEPT target.

best regards

Mart

  
My mail tool some times refuses to bottom post, especially, when I 
reply to myself. I have to jump through hoops and some time it is 
easier to submit to its demands :-)


Agreed. I set up the tables to drop and log messages whenever an 
unsolicited message comes from outside. But, I did not think
I setup the router to send periodic pings. I guess the verizon router 
(yes, it is mine because verizon gave it to me free) does that because 
it is windows centric and it likes to by user friendly by inquiring 
"are you there? I greet you, etc."


It may be a good packet or it may be a bad packet. I still do not want 
to look at unsolicited packets.  I am worried that some one from 
outside can spoof as my router. I will just drop this specific packet 
without logging it.


Specifically, what does icmp_type = 8 mean?

Ramesh





My bad, I googled icmp_type 8. It seems harmless and required to be 
implemented. So I am going to accept.
After filtering out this one, I notice another one coming from my own 
firewall and need to figure out who is sending it.


[2731831.967429] IN=eth1 OUT= MAC= SRC=192.168.1.47 DST=192.168.1.255 
LEN=233 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=138 DPT=138 LEN=213


I think this from my nmbd on the outgoing port. I am going to 
investigate interfaces option in smb.conf. Please tell me if I am on the 
wrong path.


Ramesh


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Re: Re: How to get rid of this firewall error.

2010-07-29 Thread Ramasubramanian Ramesh


top posting - iihh ugly ;-p

  
well, it's the netfilter code from the kernel instructed by an 
iptables rule, that spits out that message.

most likely this is a message informing you about a blocked packet.
  
the question is: who/what set this iptables rule to tell the kernel to 
discard such packets?

my cristal ball is currently somehow foggy, so I can't tell.
maybe you know what firewall frontend you are using?

what to do?
  
well - to prohibit logging of those packets in the short term a rule 
like this may do the job:

iptables -I INPUT -i eth1 -s 192.168.1.1 -p icmp --icmp-type 8 -j DROP

for the long term:
learn how to configure your firewall frontend or iptables.

but it's you modem/router right?
  
so it might just check if you online. so it could be a 'good packet', 
which you might want to accept. - same thing as above just with the 
ACCEPT target.

best regards

Mart

  
My mail tool some times refuses to bottom post, especially, when I reply 
to myself. I have to jump through hoops and some time it is easier to 
submit to its demands :-)


Agreed. I set up the tables to drop and log messages whenever an 
unsolicited message comes from outside. But, I did not think
I setup the router to send periodic pings. I guess the verizon router 
(yes, it is mine because verizon gave it to me free) does that because 
it is windows centric and it likes to by user friendly by inquiring "are 
you there? I greet you, etc."


It may be a good packet or it may be a bad packet. I still do not want 
to look at unsolicited packets.  I am worried that some one from outside 
can spoof as my router. I will just drop this specific packet without 
logging it.


Specifically, what does icmp_type = 8 mean?

Ramesh





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Re: How to get rid of this firewall error.

2010-07-29 Thread Mart Frauenlob

On 30.07.2010 02:49, Ramasubramanian Ramesh wrote:

It would have helped if I actually include the message :-) Here it is:

[2709614.616138] IN=eth1 OUT=
MAC=00:16:e6:84:37:c5:00:0f:db:5c:a0:58:08:00 SRC=192.168.1.1
DST=192.168.1.47 LEN=36 TOS=0x00 PREC=0x00 TTL=64 ID=37027 PROTO=ICMP
TYPE=8 CODE=0 ID=60352 SEQ=0

192.168.1.47 is my firewall connected to the DSL modem/router (which I
think must be 192.168.1.1)

Ramesh


Ramasubramanian Ramesh wrote:

Hi:

My syslog and console window is repeatedly printing the follwing
message from my firewall setup. I cannot figure out which program or
service is printing this message. My first preference is to modify the
source behavior. The second choice is to stop printing the message.
I guess I could edit the firewall script. But, I like to get some
expert feedback before I proceed this way.

Thanks
Ramesh




top posting - iihh ugly ;-p

well, it's the netfilter code from the kernel instructed by an iptables 
rule, that spits out that message.

most likely this is a message informing you about a blocked packet.
the question is: who/what set this iptables rule to tell the kernel to 
discard such packets?


my cristal ball is currently somehow foggy, so I can't tell.
maybe you know what firewall frontend you are using?

what to do?
well - to prohibit logging of those packets in the short term a rule 
like this may do the job:

iptables -I INPUT -i eth1 -s 192.168.1.1 -p icmp --icmp-type 8 -j DROP

for the long term:
learn how to configure your firewall frontend or iptables.

but it's you modem/router right?
so it might just check if you online. so it could be a 'good packet', 
which you might want to accept. - same thing as above just with the 
ACCEPT target.



best regards

Mart


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Re: How to get rid of this firewall error.

2010-07-29 Thread Ramasubramanian Ramesh

It would have helped if I actually include the message :-) Here it is:

[2709614.616138] IN=eth1 OUT= 
MAC=00:16:e6:84:37:c5:00:0f:db:5c:a0:58:08:00 SRC=192.168.1.1 
DST=192.168.1.47 LEN=36 TOS=0x00 PREC=0x00 TTL=64 ID=37027 PROTO=ICMP 
TYPE=8 CODE=0 ID=60352 SEQ=0


192.168.1.47 is my firewall connected to the DSL modem/router (which I 
think must be 192.168.1.1)


Ramesh


Ramasubramanian Ramesh wrote:

Hi:

 My syslog and console window is repeatedly printing the follwing 
message from my firewall setup. I cannot figure out which program or
service is printing this message. My first preference is to modify the 
source behavior. The second choice is to stop printing the message.
I guess I could edit the firewall script. But, I like to get some 
expert feedback before I proceed this way.


Thanks
Ramesh



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How to get rid of this firewall error.

2010-07-29 Thread Ramasubramanian Ramesh

Hi:

 My syslog and console window is repeatedly printing the follwing 
message from my firewall setup. I cannot figure out which program or
service is printing this message. My first preference is to modify the 
source behavior. The second choice is to stop printing the message.
I guess I could edit the firewall script. But, I like to get some expert 
feedback before I proceed this way.


Thanks
Ramesh


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