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 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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417 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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3answers
212 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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171 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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1answer
538 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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284 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 ...
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1answer
440 views

What is the difference between UDP hole punching and STUN? [closed]

As the title says, what is the difference between UDP hole punching and STUN? Or is it the same?
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2answers
264 views

determine connections limit enforced by my ISP

I know my new ISP is enforcing a lot of different limitations. They refuse to say what are the limits. To determine bandwidth I can use sites like http://www.voiptest.org/ (BTW it shows me ~15% of ...
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164 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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1answer
81 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
309 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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598 views

Puzzling TCP performance over 3G / UMTS

I'm using 3G as my primary internet connection, and TCP over this thing is getting more puzzling every day. For example: Downloading from kernel.org is crazy fast: $wget ...
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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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255 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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316 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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2answers
740 views

Kill UDP port that has no process?

My VPN client sometimes can't bind to the UDP port (500) it uses. It seems to leave behind a "bind" to port 500 on a previous run, even though it has quit. The port is reported as "already in ...
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369 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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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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1answer
379 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
649 views

Wake On Lan will not work no matter what

I have been having the most frustrating time trying to get my desktop computer to wake up from a magic packet. The worst part is, I am almost 100% sure that I have had it working on this computer in ...
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2answers
570 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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1answer
133 views

UDP client behaving differently for wifi router

I have a setup like, main router is connected to modem(ISP), I have connected one wifi router to main router, and another wifi router to above wifi router, so have 3 levels of routers. Now I connected ...
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1answer
772 views

Multiple connection attempts per minute on udp port 1024 - What might be the cause?

Here's a small sample from my firewall log: Sep 24 14:51:04 server Shorewall:net2fw:DROP: IN=eth0 OUT= MAC=44:87:fc:8a:f2:c3:00:04:ed:dd:e6:4a:08:00 SRC=213.5.110.105 DST=10.1.1.3 LEN=131 TOS=00 ...
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2answers
2k views

DHCP: broadcast flag

I'm looking at some DHCP packets through wireshark. I notice that in the bootp section, there is a broadcast flag. However, the dest IP is 255.255.255.255. Isn't it enough to indicate that it's ...
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1answer
244 views

A port scanner or proxy server for testing UDP (or all other) protocols on particular (or all) ports

I have a problem GPS localizer (TK102), that is probably sending out data over UDP, but my server isn't receiving it (while it does from other clients, using UDP and this IP/port). I asked on ...
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499 views

How to transfer data between two networks efficiently

I would like to transfer files between two places over the internet. Right now I have a VPN and I am able to browse, download and transfer files. So my question is not really how to transfer the ...
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1answer
184 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
173 views

Do asp.net windows server based server uses any udp packets [closed]

I am an indie browser mmorpg game developer. I am not using any streaming. Everything is http , web service or ftp. Now my question is does my server use any UDP packets? I just recently got ddos ...
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278 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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3answers
1k 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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2answers
1k views

My Mac keeps broadcasting UDP packets to 255.255.255.255:2008

The source port changes rapidly, from 49xxx to 6xxxx. I tried to use lsof -i udp, and see there's process named mDNSRespo which holds a lot of udp sockets. However, none of these sockets' ports are of ...
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3answers
902 views

How do I make netcat receive UDP packets from any host?

Is there a way to make netcat receive UDP packets from any ip:port? I don't want it to bind to a specific host as the first packet comes. I can consider alternatives, but they have to be bash ...
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1k views

how to forward and broadcast UDP packet from one network to another?

I want to forward udp packets broadcasted in one network to another. how can i do this ? I know we can put router in between and router can forward, but router can only unicast not broadcast.
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1answer
704 views

Is there Windows utility to find out which process is sending UDP packets?

The problem is: Using Microsoft Network Monitor 3.4, I can know which process created a TCP connection, but Microsoft Network Monitor cannot report which process sends UDP packets. I'm a network ...
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174 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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2answers
2k views

How to determine which process sends UDP packets periodically to an IP address?

I tried looping with netstat and but the packets are small and not frequent so do not get caught (can still see them with tcpdump). Need to know which process sends those packets.
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202 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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729 views

Use Nmap to send arbitrary data from spoofed address/port

For testing the error and timeout handling of a custom SIP stack, it is sometimes useful to send UDP packets from multiple source addresses (even ones that are assigned to other hosts) to the host ...
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2answers
69 views

How can I see the rate at which data is sent?

I have an app that sends messages over UDP in some known format. I'd like to know the rate at which these messages are sent. To be clear, I could care less about the datarate - it's a loopback, so ...
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338 views

Does TCP/UDP send file sequentially or randomnly?

Does TCP/UDP protocol always send or receive file packets sequentially? Would it possible to make a choice which data packets will be sent first using sockets API?
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1answer
563 views

VPN for specific UDP ports?

My ping to DotA 2 servers (online video game) is very poor in afternoon hours. My ping usually go as high as 300ms or even more. I tried to use OpenVPN with my dedicated server my ping decreased to ...
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1answer
174 views

What is fjappmgrbulk?

I captured a udp packet from wireshark which ones port is 2510 and destination ip is 81.64.155.202. What is that port for? I found this post) mentioning: "it's for fjappmgrbulk, fjappmgrbulk ...
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309 views

Sending a file via TCP/UDP socket

I'm reading about TCP and UDP from a article. In the end what I understood is that UDP is faster than TCP but it is unreliable. So if I'm going to a send a file, If use UDP, would it be faster than ...
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1answer
629 views

How to listen to all ports (udp and tcp) or make them all appear open in Debian

I got an external Debian server. The problem is that my university campus doesn't allow connections to go outside when the port is different than TCP port 22, 80, 443, or UDP port 123. I tested them ...
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1answer
759 views

Can I browse the web using the UDP protocol?

Is it possible to browse the web if a firewall is blocking the HTTP protocol? I've read about OpenVPN UDP tunnelling, but is it possible to use the web via the UDP protocol?
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100 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 ...
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2answers
5k views

Netcat/socat behavior with piping and UDP?

I guess this is close to linux - Netcat stops listening for UDP traffic - Super User, but I thought I'd better ask anyways As far as versions of netcat I'm using Ubuntu 11.04 and the default netcat ...
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2answers
987 views

Live video streaming over UDP?

What options are currently available for live streaming of video over UDP? Current solution uses libx264 and wowza media server, to serve up an rtmp stream. Unfortunately it's communicating over ...
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1answer
5k views

Linux built-in or open source program to join multicast group?

I'm using tcpdump to capture multicast packets and had to code up a custom program to join multicast feeds so tcpdump will "see" the packets. Just wondering if netcat or any other applications can ...
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1answer
1k views

How do I control the streaming frame rate of ffmpeg?

I am using ffmpeg to stream video: ffmpeg -i $file -f mpegts udp://hostname:port On another machine, I am using VLC to play the output stream. The problem I have is that VLC is playing the stream ...