Community discussions

MikroTik App
 
AndreiPH
just joined
Topic Author
Posts: 2
Joined: Tue Oct 18, 2016 9:02 pm

Unwanted / unclaimed high WAN traffic

Mon Mar 06, 2017 7:29 pm

Hello guys,

I have unusual high traffic on my WAN interface. Please assist me to block this, I'm new to firewall rules for Mikrotik.

Any advise on how to solve and prevent this problem in the future is highly appreciated.

Thanks in advance.
/ip firewall filter
add action=accept chain=input comment="defconf: accept ICMP" protocol=icmp
add action=accept chain=input comment="defconf: accept establieshed,related" connection-state=\
    established,related
add action=drop chain=input comment="defconf: drop all from WAN" disabled=yes in-interface="ether1 - wan"
add action=fasttrack-connection chain=forward comment="defconf: fasttrack" connection-state=established,related
add action=accept chain=forward comment="defconf: accept established,related" connection-state=\
    established,related
add action=drop chain=forward comment="defconf: drop invalid" connection-state=invalid
add action=drop chain=forward comment="defconf:  drop all from WAN not DSTNATed" connection-nat-state=!dstnat \
    connection-state=new in-interface="ether1 - wan"
add action=drop chain=virus comment=Worm protocol=udp src-port=4444
add action=jump chain=forward comment="jump to the virus chain" jump-target=virus
/ip firewall nat
add action=masquerade chain=srcnat comment="defconf: masquerade" out-interface="ether1 - wan"
/ip firewall service-port
set ftp disabled=yes
set tftp disabled=yes
set irc disabled=yes
set h323 disabled=yes
set sip disabled=yes
set udplite disabled=yes
set dccp disabled=yes
set sctp disabled=yes
1.jpg
You do not have the required permissions to view the files attached to this post.
 
User avatar
soonwai
Member Candidate
Member Candidate
Posts: 186
Joined: Mon Feb 06, 2012 10:50 pm
Location: Kuala Lumpur

Re: Unwanted / unclaimed high WAN traffic

Mon Mar 06, 2017 7:34 pm

Looks like your RB is being used in a DNS amplification attack.
Image
Ensure that you have an input-chain-drop-filter for your WAN interface.
Or at least drop UDP port 53 from WAN. That should stop the activity immediately. Like this:
/ip filter firewall add action=drop chain=input dst-port=53 in-interface="ether1 - wan" protocol=udp

I see this rule in your firewall disabled, best to enable it and accept ports to input chain only as needed.
add action=drop chain=input comment="defconf: drop all from WAN" disabled=yes in-interface="ether1 - wan"
 
AndreiPH
just joined
Topic Author
Posts: 2
Joined: Tue Oct 18, 2016 9:02 pm

Re: Unwanted / unclaimed high WAN traffic

Mon Mar 06, 2017 8:18 pm

I had the rule enabled, but with it active, the dns is not resolved over pptp...
 
jarda
Forum Guru
Forum Guru
Posts: 7756
Joined: Mon Oct 22, 2012 4:46 pm

Re: Unwanted / unclaimed high WAN traffic

Fri Mar 10, 2017 12:44 pm

Badly implemented firewall rules... You should drop new connections on wan port in forward and input chains generally. At least.

Who is online

Users browsing this forum: actomobile, Google [Bot], vshaev60 and 42 guests