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Old 06-27-2016, 04:07 PM   #1
ondoho
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firewall keeps blocking connection attempts (from router?)


i have 2 machines hooked up to a cisco EPC3828D router.
both are running the uncomplicated firewall (ufw), and its log constantly (about 1/s) throws messages about blocked connection attempts, with ip addresses from all over the world.

both ufw's are set up to allow outgoing and deny incoming.

all incoming traffic is disabled on the router.

then i remembered that the router has an inbuilt dhcp server, and i disabled that - but the connection attempts don't stop!
only now most of them (not all!) seem to be coming from the router itself(192.168.0.1):
Code:
[ 2732.269185] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 2858.309086] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 2984.339022] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 3110.368968] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 3133.124332] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=82.24.169.49 DST=192.168.0.10 LEN=131 TOS=0x00 PREC=0x00 TTL=111 ID=21586 PROTO=UDP SPT=27698 DPT=54186 LEN=111 
[ 3236.398881] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 3362.428756] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 3488.468647] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 3614.498567] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 3740.528462] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 3866.558384] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 3992.588314] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 4118.628188] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 4244.658083] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 4370.687993] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 4496.717887] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 4622.747804] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 4668.666563] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.177.36.186 DST=192.168.0.10 LEN=129 TOS=0x00 PREC=0x00 TTL=46 ID=63937 PROTO=UDP SPT=6889 DPT=54186 LEN=109 
[ 4748.787643] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 4874.817582] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 5000.847440] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 5126.877346] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 5252.907219] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 5378.947084] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 5504.976980] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 5631.006858] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 5742.964978] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=50.4.166.211 DST=192.168.0.10 LEN=77 TOS=0x00 PREC=0x00 TTL=116 ID=28681 PROTO=UDP SPT=16983 DPT=48685 LEN=57 
[ 5757.036734] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 5883.066622] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 6009.106534] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 6135.136360] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 6261.166220] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 6387.196124] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 6391.151793] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=28764 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6391.155953] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=28770 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6391.163346] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=28779 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6391.172107] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=28789 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6391.180548] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=28799 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6391.188641] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=28809 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6391.196844] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=28819 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6403.137267] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=30994 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6403.145040] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=31003 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6408.091899] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=92.113.42.118 DST=192.168.0.10 LEN=145 TOS=0x00 PREC=0x00 TTL=113 ID=31902 PROTO=UDP SPT=49001 DPT=48685 LEN=125 
[ 6513.225966] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2 
[ 6614.199086] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=50.4.166.211 DST=192.168.0.10 LEN=77 TOS=0x00 PREC=0x00 TTL=116 ID=28682 PROTO=UDP SPT=16983 DPT=48685 LEN=57 
[ 6639.265889] [UFW BLOCK] IN=eth0 OUT= MAC=nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn:nn SRC=192.168.0.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=0 PROTO=2
i only changed the mac addresses (2 different addresses).

wth is going on?
i thought i told the router to not allow any incoming traffic to come through to the machines?
no port forwarding, no port triggering. no upnp, no dmz, no fancy stuff at all.

i am browsing the web and listening to music, but that shouldn't be interpreted as incoming requests?

how are they getting through the router to my computer?

i need a sanity check here, at the very least.
or maybe it is time to panic.

incidentally, i wonder if i can tell ufw to log to a file.
it's flooding the console on my non-gui machine.

Last edited by ondoho; 06-27-2016 at 04:12 PM.
 
Old 06-28-2016, 09:57 AM   #2
Habitual
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Have you seen https://en.wikipedia.org/wiki/Multicast ?

I tried blocking this "noise" once, and failed.
Learned to live with it.
 
Old 06-28-2016, 12:10 PM   #3
lazydog
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Might want to look into log limiting so your logs do not fill up with the same information.
 
Old 07-12-2016, 08:55 AM   #4
ondoho
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yes, it seems to be harmless.

Quote:
Originally Posted by ondoho View Post
incidentally, i wonder if i can tell ufw to log to a file.
it's flooding the console on my non-gui machine.
i found a solution for that.
had to edit a file in /etc to disable logging to console. systemwide, not for ufw only.
i just took 5min to find that file, and couldn't.
sorry, i did this 2 weeks ago just before leaving on holiday.
if i remember, i will post it.

ufw is still filling the journal.

i edited /etc/journald.conf to limit the journal size, i hope it works as expected on debian stable (transition from initv to systemd?).
 
  


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