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.

learn more… | top users | synonyms

1
vote
1answer
57 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 ...
0
votes
2answers
102 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 ...
0
votes
1answer
359 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 ...
1
vote
0answers
944 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 ...
2
votes
2answers
4k views

How to detect if network is dropping UDP packets?

I'm got a video streaming application that runs fine in my office but fails miserably at the customer location. The symptom is that every couple of seconds, I stop receiving UDP packets for 2 seconds, ...
0
votes
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 ...
0
votes
2answers
171 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 ...
0
votes
1answer
104 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 ...
2
votes
2answers
3k 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 ...
0
votes
0answers
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. ...
0
votes
1answer
743 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 ...
2
votes
0answers
427 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 ...
0
votes
0answers
172 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 ...
1
vote
1answer
489 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 ...
1
vote
3answers
264 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 ...
1
vote
0answers
213 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?
1
vote
1answer
757 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 ...
1
vote
1answer
399 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 ...
-1
votes
1answer
562 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?
0
votes
2answers
365 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 ...
1
vote
0answers
222 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 ...
1
vote
1answer
110 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 ...
1
vote
1answer
350 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 ...
8
votes
2answers
729 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 ...
0
votes
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 ...
0
votes
0answers
326 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 ...
1
vote
0answers
395 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 ...
1
vote
2answers
994 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 ...
1
vote
0answers
447 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 ...
0
votes
0answers
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 ...
1
vote
1answer
465 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 ...
0
votes
2answers
780 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 ...
1
vote
2answers
696 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 ...
0
votes
1answer
155 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 ...
0
votes
1answer
1k 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 ...
2
votes
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 ...
1
vote
1answer
288 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 ...
0
votes
1answer
603 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 ...
1
vote
1answer
211 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. ...
0
votes
1answer
227 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 ...
2
votes
0answers
319 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 ...
5
votes
3answers
2k 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 ...
0
votes
2answers
2k 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 ...
0
votes
3answers
1k 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 ...
1
vote
2answers
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.
2
votes
1answer
812 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 ...
2
votes
0answers
193 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 ...
1
vote
2answers
3k 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.
2
votes
0answers
213 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, ...
0
votes
2answers
932 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 ...