UDP stands for User Datagram Protocol. With UDP applications can send messages (datagrams) to other hosts on a network without requiring prior communications to set up special transmission channels or data paths.

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Changing the ports a program uses

This question might not even make sense. I have a very limited understanding of how networking protocols work. My phrasing of these questions might be very poor. My school has a firewall enabled. ...
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514 views

Force DNS resolution to use TCP

My Comcast internet connection has been giving problems in DNS resolution, and I am guessing the reason is a probably broken or limited UDP. I am currently working around it by tunneling over TCP ...
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2answers
763 views

TCP/UDP hole punching from and to the same NAT network

I was wondering if tcp/udp hole punching would still work when you are in the same network (behind a NAT), and what the packet's path would be. What happens when using hole punching on the same ...
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2answers
36 views

VNC (or RDP) server using outbound connection only

How do I set up a VNC server that connects to an intermediary server to start an outbound communication, that can be used by a VNC client. This way the port forwarding doesn't need to be set up, and ...
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2answers
511 views

UDP Flood to Host in the firewall logs

When the router's firewall logs shows as follows UDP Flood to Host PRIVATE_LAN_CLIENT_IP, PORT ->> EXTERNAL_PUBLIC_IP, PORT (from WAN Outbound). Will those packets be routed to the private lan ...
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114 views

Port forwarding beginner

I have been trying to set up port forwarding for the past 48 hours and I can't quite get it. I have used online port scanners to see what ports are open and they are saying none, not even the port I ...
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72 views

Testing a Firewall against outgoing UDP ports

I'm trying to test which outgoing ports are allowed through a firewall. At the moment I can do this for TCP by port scanning portquiz.net (which is a server with all TCP ports open) from inside ...
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1answer
95 views

How to experience UDP hole punching using Ncat under Linux?

I'd like to see UDP hole punching in action. I tested it under Linux, using Ncat. Here's what I tried: Open port 1234/UDP on host A and port 12345/UDP on host B's firewall (I'm still behind NAT, but ...
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1answer
191 views

What is the difference between UDP and HTTP torrent trackers?

In the context of bittorrent what's the difference between http and udp trackers? HTTP is an application layer protocol and UDP is a transport layer protocol so the concepts seem non-overlapping. I ...
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1answer
105 views

Emulate console by sending data on one UDP port, and receive text from another

I'm trying to establish a “console-like” connection with a National Instruments cRIO-FRC. It broadcasts its console output onto 255.255.255.255, UDP port 6666. I can listen to it with: socat ...
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1answer
540 views

“udp relay” via openssh socks proxy

I'm trying to run a UDP based multiplayer game (dota 2) via the following chain dota2 (OS X)-> proxycap -> ssh tunnel -> home machine (OS X) -> internet The home machine is running the ...
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1answer
132 views

How to optimise a Motorola Wing 5.3 Access Point for UDP traffic

I have a motorola wing v 5.3 which I need to optmise for UDP traffic. I have some UDP packet loss and I think that if I change the AP configuration I would get a better result. Anyone has experience ...
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370 views

IP checksum offload

I recently updated to Windows 8 and get alot of invalid packet transfers. It says "Ip checksum offload?" (Wireshark) and most of my packets get lost. The checksum is 0x00. I also updated my NIC ...
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1answer
235 views

Log is full of “stealth mode connection attempt”s

My daily log is full of messages like: 8/25/12 8:27:01.385 PM Firewall: Stealth Mode connection attempt to UDP 192.168.1.101:40959 from 109.254.109.20:1098 where 192.168.1.101 is IP of my mac. ...
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1answer
3k views

UDP blocked by Windows XP Firewall when sending to local machine

I work for a software development company but the issue doesn't seem to be programming-related. Here is my setup: Windows XP Professional with Service Pack 3, all updated Program that sends UDP ...
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1answer
629 views

Play UDP stream in VLC?

I receive an UDP video stream of which I know both the IP adresses and the incoming and outgoing ports of both computers. How can I plat his in vlc? udp:@:1234 Doesnt work for me. How to fix this?
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1answer
129 views

Tunnelling UDP Traffic Through OpenVPN

Referring to this answer I'm trying to route UDP streaming through an available OpenVPN tunnel. On the VPN client machine, I've access to a UDP stream over an IP (udp://1.2.3.4:5555) which I want to ...
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1answer
87 views

WPA blocks UDP broadcast

I use a convenient program called KDE Connect to interface a Linux/KDE computer with an Android device. It uses UDP broadcast. And it worked fine when my wifi was not encrypted. I recently had to ...
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1answer
412 views

DNS: can't dig 8.8.8.8 directly

me@ubuntu:# dig @8.8.8.8 google.com ; <<>> DiG 9.9.2-P2 <<>> @8.8.8.8 google.com ; (1 server found) ;; global options: +cmd ;; connection timed out; no servers could be ...
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879 views

UDP packet and firewall

I notice when I send udp packets from computer A to computer B, B can receive the upd packets correctly but if I send udp packets from computer B to computer A the udp packets are not received A and ...
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1answer
2k views

Connecting Android via wifi to Wifly RN-XV RN-171 using Access Point (soft AP) mode not working

I hope somebody has encountered this problem and knows how to fix it. I purchased a Roving Networks RN-XV module to communicate directly with an Android device. I thought it would be perfect because ...
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476 views

Dropbox LAN sync - hint for an IP address

In my work network UDP broadcast networks are isolated between the WiFi and wired channels, so LAN sync discovery does not work. Is there a way to explicitly tell Dropbox to try a specific IP address ...
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247 views

Tunnelling TCP connection through NAT

My server is in my school's NAT and my desktop computer is in my home NAT. I want to SSH to my server from home. I normally used school's VPN, but recently for some reason I can't. So I'm looking for ...
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352 views

Can I get UDP Hole Punching with (any) VNC client to get around the local firewall/router?

I don't have access to the local internet router, so I'm unable to setup port forwarding on my lan connection. I'm just trying to find out if there is any way for me to get around my local router ...
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205 views

in wireshark how to know if packet was send to vpn or to internet?

Thanks to my previous question when vpn is connected intenet is not accessible I have configured VPN connection so I can use internet at the same time. Right now I write this post and I'm connected to ...
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219 views

Mounting an NFS share with udp or mntudp options

According to the documentation of NFS client on Mac OS X 10.7 user can specify following options: udp Use UDP transport protocol. and mntudp Force the mount protocol to use UDP transport, ...
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Forward all TCP and UDP connections over VPN

I have the following setup: OS: Ubuntu v13 Software: PPTP NIC 1 (eth1) IP: 10.2.95.207/24 Gateway: 10.2.95.1 (this is the network I want to connect to) NIC 2 (eth2) IP: 7.82.176.254/8 (the network ...
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37 views

OpenVPN sans port forwarding on unfriendly networks

I have a problem. I'm about to move onto campus right in the middle of the semester. For a student, I have a complicated network setup where all of my systems are reliant on NAS and all of them VPN ...
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37 views

Home router config to allow for UDP broadcast

I have a homegrown piece of software that "listens" to UDP traffic at 255.255.255.255:5010. It works just great on my home network, but does not work on other people's networks. I think that my ...
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194 views

Re-stream (forward) UDP-Live-Video-Stream (using winsock) reduce video quality?

So, I used ffmpeg to stream the live webcam using UDP protocol to port 1111 : ffmpeg -f dshow -i video="Lenovo EasyCamera" -f mpegts udp://localhost:1111 When I played it directly by ffplay from ...
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71 views

Is it possible to edit TCP and UDP packets?

Is it possible to edit the UDP and TCP packets a program sends? For example, we have a program that sends some information to its server. But we don't want to send some information that might be ...
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1k views

FFmpeg/avconv and UDP - connect listener after sender?

I'm trying to troubleshoot a port binding issue in avconv/FFmpeg. I have two test commands; one which sends an audio stream over UDP: avconv -i test.wav ...
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236 views

Artificial network delay tcp/udp (bigger ping) for defined application? (windows)

I have a game where people can easy detect who i am looking at my ping, i want to make my ping highter. How can i set network delay for all network connections for defined application?
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495 views

What is blocking incoming packets to port 67?

I have a DSP connected to a Windows 7 laptop by Ethernet. The laptop has all firewalls disabled (I’ve even tried stopping the Windows firewall service and DHCP). The DSP is sending well-formed BOOTP ...
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70 views

COD4 Linux game server doesn't send UDP packets as response to broadcast

I am setting up a bunch of Game servers for a medium sized LAN tournament using CentOS 6 and the various Linux binaries used for the game servers. With COD4 the servers did not show up in the server ...
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20 views

Do I need to join a multicast group to send a packet or joining is just for listening?

I am confused here. Can anyone just send a packet to a multicast address and port? Where does the multicast group come into play here? Do I also need to send to a group? Can someone explain that to ...
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37 views

How to create a wireless-to-ethernet router?

I have a Debian machine, which I want to turn into a router. It will connect via wireless to a access-point, where it will get an IP. To its ethernet port, other machines will be connected. It will ...
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311 views

Streaming screen over LAN with VLC using RTP

I am trying to stream the screen (video and audio) from a Windows PC to a Linux one (Raspberry Pi), using VLC. I have tried emitting the screen through RTP (I want to do unicast), and then in the ...
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802 views

udp client sending ICMP “port unreachable” when receiveing messages from the server

(Note: I moved this question from StackOverflow, because it's to be considered off-topic there, better fits here, and still unsolved) I have a udp client using luasocket, basically doing this (with a ...
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258 views

UDP port binding to loopback interface

I've been trying to play a video game in multiplayer, but after trying a lot of time, I begun to realize there was some problem with my loopback interface (Windows 7) I have UPnP activated in my ...
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224 views

How to use netperf on specific NIC port?

I have two servers, SERVER and CLIENT and each server has its own onboard 1 GbE ports, and its own NIC with a 10 GbE port. SERVER and CLIENT are interconnected on both a 1 GbE switch (administrative ...
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53 views

UDP causing problems with other connections

I have implemented a file transfer program on Windows 64-bit platform using winsock API. I am using a 1Gbps connection. When I transfer files using TCP protocol, I am getting only 320 Mbps. when I ...
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148 views

Send data from file to local UDP port

I've got an application, A, that listens on a user-defined UDP port for a specific message that normally comes from another application, B. Application B has a tool that allows recording these ...
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1k views

How to direct a UDP Packet through a vps tunnel?

How to direct a UDP Packet through a VPN Tunnel over a WAN? Have been trying to set up a instant messenger service though the office network and it dose not have UDP flooding or UDP broadcasting. ...
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186 views

UDP NAT punching for linksys wrt54g

I could not explain the strange NAT behavior, hope someone could help: I have a linksys wrt54g router at home. Client sends UDP keep alive packet from 192.168.1.20:16688 (nat outside public IP/port ...
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351 views

What would cause different rates of packet loss between client and server in UDP?

If I've implemented a reliable UDP file transfer protocol and I have a file that deliberately drops a percentage of packets when I transmit, why would it be more evident that transmission time ...
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2k views

RTP input stream on VLC

I'm trying to play on VLC a RTP input stream coming from the port 9954, UDP socket. So, I launch VLC on the console with this command: vlc -vvv rtp://:@9954. VLC appears, but no media is played. The ...
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110 views

windows xp irregularly refuses to connect to one specific webserver

I think of myself as an advanced user but this problem is driving me batty. Windows XP (32bit Home) going through a WRT54G router, once or twice a day at completely different random times, refuses to ...