UDP coming in firewall?

NYGiantsFan
NYGiantsFan used Ask the Experts™
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It appears UDP packets are coming from the Internet through the Firewall to specific servers.  

Anyone have any idea how this might have happened?  The firewall solution was IPtables.

Any thoughts would be appreciated.
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Commented:
It would help if you gave the source and destination ports. They could be return traffic for connections initiated by the servers. You should also be aware that Unix systems use UDP ports 33434 to 33534 for traceroute so are you allowing these in from the outside?

Author

Commented:
I will get those ports shortly. The firewall has NAT. The Destination IP was a private IP address.  (10.16.0.15)

Author

Commented:
Hi,
The source IP address port was 25033 and the destination IP address is 2877.
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Top Expert 2014
Commented:
Is the traffic coming into your firewall with the destination IP address of 10.16.0.15, or is this what the public IP address is NAT'ed to?

If 10.16.0.15 is what the NAT translates to, is that IP address valid on your network?

Does is have a service/task listening on UDP port 2877?
Senior CyberSecurity Engineer
Commented:
UDP traffic is a legitimate type of traffic for many protocols

so unless we know what your allowing and blocking
protocol wise
its hard to say

was the traffic originated from outside or did your system generate something and your only looking at the return session???

IPTables is a very sinple FW at best

it can be tweaked and used to control traffic to a degree but IT IS NOT a legitimate Enterprise solution

that's why there are several Networking/security companys making the big bucks selling FW
even a open source FW would provide more than IPTables

Author

Commented:
My question was rather vague.  I will refine the question.  Thank you everyone for your thoughts.

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