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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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682 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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199 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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342 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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781 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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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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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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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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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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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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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 ...
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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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628 views

Is there a userspace bandwith limit tool for Linux?

I want to limit the upload bandwidth of a P2P live video program, which is closed source, in Linux. I don't want to use tc because I don't have root access. There is a tool called trickle, but ...
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Does it matter what UDP port a WOL signal is sent to?

i have seen many WOL instances use port 7 and many use port 9, does it matter? Isn't it just looking for a WOL packet at layer 2 or ethernet?
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How to use DNS over TCP?

Google DNS (8.8.8.8 and 8.8.4.4) are blocked (or polluted) by all ISPs available to me (and DNS by ISPs just return wrong answers for some sensitive sites!!), and it is said that if we change DNS from ...
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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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Comparison: UDP vs TCP [closed]

UDP vs TCP. What are these ? What are their Differences, pros and cons ?
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Which element of network refused connection

How could I determine, which element of the network actually refused/closed the connection?
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How to stream my media via vlc using udp streaming method?

I would like to know how to stream my media via vlc using udp streaming method?
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Detect all computers running a service on a network

I'm trying to write a file synchronization protocol presently (consider it a hobby, I know there are plenty of file synchronizers out there) and I wanted to create a way to automatically sync things ...
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Mcafee Host Intrusion Protection blocks all-in-one network printer

I just bought a new HP Officejet 6500 printer. It has a built-in ethernet port, so I happily connected it to my network. While I was playing around with it, I saw that it stopped responding ...
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Force OS X to use SOCKS5

Currently I am using an OpenSSH session (with the -D flag to enable dynamic application level port forwarding) as a SOCKS proxy while I'm accessing the internet through an unencrypted wireless access ...
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Windows 7: how to redirect dhcp traffic to alternative port

I was hoping someone could help me find a way to force DHCP traffic to use an alternative port on Win7. I need windows to send and listen for dhcp traffic on a port other than 67/68. I have tried to ...
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How to deliberately introduce a delay for incoming UDP packets

I want each packet (that match iptables rule) to be delayed by some fixed time interval. How to to this? Preudocode: iptables -A INPUT -p udp <more conditions> -j DELAY --delay 50000 # delay ...
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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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Can I use TCP as DNS query protocol on Mac OS?

I'm using Mac OS, Snow Leopard 10.6.2, and I'm suffering from UDP packet loss during DNS query. So my web browser is too slow to surf internet nicely. But it worked very well when I tried a DNS query ...
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What does this UDP Packet mean?

I'm total newbie at tcp/ip and I was experimenting with Wireshark. What this mean: 1824 578.194204 xxx.xxx.xxx.xxx yyy.yyy.yyy.yyy UDP Source port: 17500 Destination port: 17500 In data I ...
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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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How do I establish a connection between 2 computers on different subnetworks?

computer A(192.168.1.134) needs to establish a UDP connection to computer C(192.168.0.30). As you can see both are on a different subnetwork. Now I have computer B which has 2 IP addresses, one for ...
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Why is it bad to have open ports?

Here's something that has always baffled me. Why is it bad to have open ports on your computer? Assuming you don't have a virus on your computer or some other program listening to a port that may ...
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What typically uses port 44380?

A company just asked me to open port 44380 in my firewall so that their software could work. This made me wonder... what is the customary use for port 44380?
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Good process specific packet sniffer / viewer?

I am looking for a good, free or not free, packet sniffer. The main feature I am looking for is an ability to watch a chosen process and view / read all of the data it is sending or receving. Also I ...
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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 ...