Security Basics mailing list archives

RE: Home firewall Hits


From: "Preston, Tony" <Tony.Preston () acs-inc com>
Date: Thu, 6 Nov 2003 16:19:08 -0500

Actually, I found that I had turned on the logging feature on the Linksys
router and it was sending me the messages, not a port scan.  It is
interesting to use WallWatcher to see what it going on on my home network...
I can see where my son is surfing ...:)  It did look like a port scan to me
which was why I asked my questions.

BTW... I do have a firewall on my Win/ME system.  As for the 67/68 hits, I
guess I may have misconfigured my firewall to block those, my question  was 
What did the hit mean:

31/Oct/2003 00:00:02] Rule 'Packet to unopened port received': Blocked: In
UDP, 0.0.0.0:68->localhost:67, Owner: no owner


I think I know now from doing a bit of research that one of my firewall
rules was blocking something that maybe I should let through...   I am
tempted to leave it blocked since it doesn't seem to be needed.

Everyone was pretty helpful... thanks again.

Tony Preston
Systems Engineer, AS&T Inc.
Division of L3 Corporation
(609) 485-0205 x 181


-----Original Message-----
From: me null [mailto:me_null () hotmail com] 
Sent: Thursday, November 06, 2003 3:27 PM
To: Tony.Preston () acs-inc com; security-basics () securityfocus com
Subject: Re: Home firewall Hits

hello, i havent read through the replys you have got but ill chime in non 
the less. i would amagine some have sayed part of what i will.

1 im not sure what u ment here bout it sounds like a port scan

">From reading the firewall log, I would think that my router is 
continuously
hitting
Port 162  with a UDP message.  The odd thing is that it is doing this by
using an
incrementing port from  192.168.1.1, I see many of these every day, it is
continuous."

2 these are DHCP ports 67 / 68 UDP a DHCP server would tell DHCP clients 
where thay are and info regarding you network.

3 is this is EXACTLY your setup ...
" [cable modem] <----> [ Linksys Wireless Router] ~~~ [ Windows ME W/
firewall ]"
than theres nothing blocking access from the internet to your router. witch 
means some 1 can (if thay havent yet) crack you routers password. you would 
be amased at how easy this can be like a user name of "admin" and a password

of "admin" and BAM thay have CONTROL of your router. either put a fire wall 
between your router and the internet or ATLEAST change you login credintals 
for your router

hope this helps and wasnt too redundant


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