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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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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263 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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2answers
3k views

OpenVPN client behind corporate firewall

I cannot connect from the corporate network at work to my OpenVPN server. However, with client and server settings untouched, connecting from other networks works. I can only assume that this is due ...
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515 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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1answer
116 views

DNS Resolver for Windows over TCP

I know that DNS uses UDP with Port 53 for DNS queries. However, at my place sometimes UDP requests are blocked and DNS fails. I know that there is protocol for DNS over TCP and many public DNS servers ...
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3answers
1k views

How to force a process transmit over UDP instead of TCP?

I 'm running an ffserver process on a Linux machine, in order to achieve video streaming via ffmpeg. However, there is a delay on video streaming. On ffserver configuration file I define Port 8090. ...
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55 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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2answers
7k views

Netcat stops listening for UDP traffic

I am using netcat on some Linux machines (see this other question), but seeing some unexpected behavior. Unlike the guide in the accepted answer, I am not using UDP tunneling to do DNS queries. I ...
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2answers
181 views

Can using UDP and OpenVPN lead to file corruption?

I know with TCP that it always checks your files to ensure nothing got fragmented or lost or destroyed. So if I use UDP for OpenVPN to download files or access an internal network, does that mean I ...
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2answers
316 views

UDP communication through proxy

I have following scenario: PC B must be capable of full TCP/UPD connectivity, so I'm testing scenario with typical FPS game. ProxyCap is proxifier software, that can connect to outside world ...
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1answer
34 views

How does an ADSL modem tell which local client to associate with each response from a server?

Does an ADSL modem generate a random string for each request I make and when response comes it directs it to my computer (but not to my phone)?
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2answers
12k views

How to generate UDP packet

I want to generate UDP packet to test a program, something equivalent to using telnet to test TCP port (Can telnet generate UDP packet?) How can I do this?
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1answer
2k views

Linux SOCKS5 tunneling not working with udp traffic

I am using the command ssh -N -D 0.0.0.0:1080 localhost which works perfectly fine for my web browser, but when I try and tunnel a UDP traffic application it doesn't work. I thought that socks5 ...
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2answers
11k views

what is type of ICMP packets? TCP or UDP

ping packets is a type of ICMP packets.Is there any relation between ICMP with TCP.In other can we guaranty their arrival in the network I want to know ICMP packets in the network is tcp or udp or ...
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1answer
136 views

How to monitor TCP and UDP port changes

I am running software on a server that may be turning off some ports and need to find out what it is. I have the ports I need to check. I just need to find out what is turning them off. How can I ...
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1answer
560 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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3answers
5k views

Proxifier that supports UDP?

Im looking for a proxifier that forces all Windows traffic through a specific proxy. I have my own server so I can ultimately configure any type of proxy (Socks, HTTPS, etc) so thats not a problem, ...
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2answers
5k views

Why is my UDP so slow?

I'm using Iperf on two VMs and when using TCP I find the performance is as follows: notroot@ubuntu:~$ iperf -s ------------------------------------------------------------ Server listening on ...
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3answers
940 views

Broadcast address in IPV4

I have a small network with the subnet mask 255.255.255.240 and the IP range is 192.168.2.1 - 192.168.2.12. From 192.168.2.1, I want to broadcast a packet. I don't want this packet to go anywhere ...
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1answer
295 views

Using and testing UDP data over the internet [duplicate]

I have a GSM modem that sends data via UDP (it appears) I have configured it to send all data to my public IP address over the internet but no data is arriving at my end so I need to troubleshoot. I ...
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1answer
122 views

Are all internet file downloads using FTP protocol?

I heard, FTP is used to transfer files over a network. Also heard that it uses TCP port 20 and 21. So TCP is connection oriented. We have acknowledgments. If the transmission is lost, we should be ...
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1answer
3k views

What range of UDP ports may rtsp use, to configure a firewall?

To allow incoming rtsp streams, I must open incoming TCP port 554. I must also open a range of UDP ports. 6970 through 6999, says http://comments.gmane.org/gmane.comp.security.shorewall/660 . At ...
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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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1answer
377 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
696 views

How does a proxy know where to forward the requests to?

When a proxy receives a connection how does the proxy know where to forward the request to? For example in Java we can set a system property for proxy. So we set the IP of the proxy and the request is ...
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1answer
885 views

Are UDP packets firewall proof?

I have been testing this "bittorent sync" software (a peer to peer application) as an experiment. I decided to block the application using the Windows firewall on the computer that is running the ...
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1answer
160 views

Wake-On-LAN and Access Control List with Mac over Internet

I am researching the best way to wake my computer through a firewall over the internet remotely (the computer to be woken is a Mac). Through external research, I have seen that I should be able to ...
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1answer
1k views

Limit UDP outbound traffic to loopback (localhost) instead of eth0

Atm i'm testing it on Ubuntu Server at VMware Workstation + Windows 7 local host with bridged connection. Later this has to go to live server. I have VLC streaming video file on Ubuntu with cvlc ...
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1answer
2k views

netcat udp address already in use

I am trying get a response from the server by using the command echo 'my message' | nc -l -u 127.0.0.1 2947 But I get nc:Address already in use. for a response. How do find the reason for this ...
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155 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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1answer
66 views

TCP vs UDP Error-Checking

I've bounced upon two articles that describe in-depth on how TCP and UDP connections work. However there is some kind of inconsistency. Where one article tells me that UDP does no Error-Checking at ...
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2answers
115 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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1answer
425 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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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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3answers
326 views

UDP checksum inconsistency between sender and receiver

I want to write a program to generate udp checksum. to validate my progra, I need some real data. I send a udp packet from one machine to another machine, the packet can be correctly received by the ...
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1answer
2k views

vlc part of desktop streaming to <host>:<port>

With VLC, I wish to stream a portion of the desktop and send it to another host on my local area network. The capture seems to work, I see a correct portion of the desktop into the VLC server, but ...
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2answers
218 views

Is sending syslog events over udp secure?

I'm considering using a service from papertrailapp.com (other similar services are loggly and splunk), where you configure your syslog to echo events to it over udp. It involves adding this entry to ...
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3answers
410 views

How can I open a TCP/UDP connection on Linux?

I am looking for a simple command line tool to open TCP/UDP server/client on a desired port on a Linux machine. Are there any applications or commands that I can use to achieve this?
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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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1answer
939 views

How to get rid of UDP checksum error messages in virtual console?

Whenever I am streaming a video in the web browser, while connected to my school LAN via ethernet, and switch to the virtual console (ctrl-alt-f1) on Ubuntu, I get an error that looks like the ...
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1answer
109 views

My laptop can't find a device that is connected to a my router but my other laptop can find it

I have this device that uses port 80000 and UDP. It came with a program that communicates with it. However, my laptop (laptop A) can't find that device using the program. So I tested the program to my ...
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1answer
135 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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1answer
923 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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0answers
483 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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1answer
593 views

ffmpeg udp audio livestream

Having trouble getting the following command to stream audio through udp, is there a parameter missing? ffmpeg -f alsa -ac 1 -i hw:1 -ar 44100 -f mpegts udp://10.255.255.255:10000?pkt_size=1316 The ...
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194 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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3answers
3k views

NAT and UDP replies

Sanity check please. If I send UDP packets from Machine A behind a NAT to Machine B's port N, where Machine B is outside the NAT (elsewhere on the Internet), can I reasonably expect that NAT to pass ...
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444 views

Routers and NAT hole punching? [closed]

I'm trying to understand why UDP hole punching works. Given peers A, B behind a NAT router and Server with port 80 open. A sends a packet to Server from port 1234. This causes the router to open a ...
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241 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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490 views

How to wrap an UDP connection to improve resistance agains packet loss?

Suppose there is UDP connection that does not expect much packet loss. Are there already tools that allow wrapping a UDP connection to gain more reliability at expence of bandwidth and overhead, for ...