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IMTheNachoMan
Asked: 2018-03-24 18:36:49 +0800 CST

packets from port 1900 to port 49125

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I have a TP-Link Archer C7 router and a Debian 9.4 server that has UFW installed on it. I was looking through the UFW logs and it looks like my router is sending requests to port 49125 of server every 30 seconds. I cannot figure out how to diagnose this.

My router is 192.168.1.1 and my server is 192.168.1.100. Here is an excerpt from the UFW log file. Does anyone know what this could be?

Mar 23 22:28:12 mydebianserver kernel: [  769.900902] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:28:32 mydebianserver kernel: [  789.900838] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:28:52 mydebianserver kernel: [  809.900581] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:29:12 mydebianserver kernel: [  829.900395] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:29:32 mydebianserver kernel: [  849.900548] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:29:52 mydebianserver kernel: [  869.900169] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:30:13 mydebianserver kernel: [  890.428246] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:30:32 mydebianserver kernel: [  909.899898] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:30:52 mydebianserver kernel: [  929.899368] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:31:12 mydebianserver kernel: [  949.899450] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:31:32 mydebianserver kernel: [  969.899535] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:31:52 mydebianserver kernel: [  989.899162] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:32:12 mydebianserver kernel: [ 1009.899015] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
Mar 23 22:32:32 mydebianserver kernel: [ 1029.898800] [UFW BLOCK] IN=eno1 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx SRC=192.168.1.1 DST=192.168.1.100 LEN=287 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=1900 DPT=49125 LEN=267
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1 Answers

  1. Best Answer

    The UDP port 1900 is used for Simple Service Discovery Protocol (SSDP), a part of UPnP. The router is probably not sending requests but responding to the request made by your server.

    If you don't actually use UPnP for anything, you may want to disable it as it's known for several security issues and abuses during years.

    Disabling UPnP on your TP-Link Archer C7:

    1. Choose menu "Forwarding→UPnP".
    2. If Current UPnP Status = Enabled, press button Disable.

    This should also stop these lines to appear in your UFW log.

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