Port 49152/udp always open?

We have a small custom board that detects SNMP traps (on port 162 usually). This is the only socket listening in our code. Apparently when i do a port-scan with nmap -sU i get the following:
162/udp open|filtered snmptrap
49152/udp open|filtered unknown

It seems that tinyclr replies with ICMP destination unreachable except for these two ports. The first one is mine but who is 49152 and how do i get rid of it?

My first guess was debug, but I can’t find any reference to that port in the PK.

Debug is what i fear too. This is a commercial application and exposing a debug interface would be a serious security issue!

@ jobe - Does the port remain if you create a new Micro Framework project and just initialize the network interface?

Yes the port is always reachable as soon as i set an IP on my interface.

i.e

       var eth0 = new GHI.Networking.EthernetENC28J60(
            SPI.SPI_module.SPI2,
            G120.P1_10, // chip select
            G120.P2_11, // external interrupt
            G120.P1_9   // reset
            );
        eth0.Open();
        eth0.NetworkInterface.EnableStaticIP("10.0.0.89", "255.255.255.0", "10.0.0.254");

With “Release” build is enough to get:

49152/udp open|filtered unknown

@ jobe - As far as I know, we do not open that port for anything. It is possible it is for debug, we will have to take a look though and see.