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firewall log question

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comox

IS-IT--Management
May 14, 2003
4
CA
Hi, I have TINY firewall ( software ) running on a W2K machine, and noticed the following in the log file.

'Packet to unopened port received': Blocked: In UDP, 192.168.1.1:1521 -> localhost:162

'Packet to unopened port received': Blocked: In UDP, 192.168.1.1:1522 -> localhost:162

'Packet to unopened port received': Blocked: In UDP, 192.168.1.1:1523 -> localhost:162

and on and on,

this has been occurring for the past few days, and the router (192.168.1.1) port runs from 1026 to 16000, and repeats, with approx 2 lines per minute.


Is this initiating from the router? Or is this something that may be incoming from outside? The network has been slower than usual.

Thanks for any input.
 
Port 162 UDP = SNMP traps. That is how Linksys routers transmit their router logs.

All of your blocked packets are inbound (localhost). Your firewall appears to be doing exactly what it's supposed to do - blocking a port that has not been opened by any program.

Is your router configured to send SNMTP traps to your workstation PC?


Vince
_____________________________________________________________
[*** If everyone is thinking alike, then somebody isn't thinking. ***]

 
Thanks,
Would the router's NAT or DHCP be responsible for the traps?
How much of a strain is this on the network?
Also wondering why this would have only started showing up the past few days, I havent made any changes to the router setup.

 
I would look at changes made in your TINY firewall setup to request, enable or create the traps and thus your log traffic. The number and alert nature of the traps might be a sign worthy of concern.

A router can stand very high traffic levels (I seem to recall reported testing levels of 100K port accesses per hour) without any noticeable problems. A strained network should be evident.

Vince
_____________________________________________________________
[*** If everyone is thinking alike, then somebody isn't thinking. ***]

 
Perhaps you may look at the statistics/errorlogs on the router (web/console/telnet/ssh/client-app... don't know the linksys). Probably the router was already configured to send SNMP-traps in case of errors and now it's time look why it starts doing so.
chris
 
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