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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How to tunnel UDP traffic with pptpd VPN?

I've set up a VPN on a Debian (7.8) server. On a Windows 8 machine, I can set up a VPN connection to the server and it works fine for TCP applications. Everything is going through the VPN. However, ...
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12 views

Route only on output chain?

I have two machines A and B. I want to send iperf traffic from A to B, but first have it route through a userspace program on A. I did this with a tunneling device: therefore, I used the command ip ...
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20 views

SYN/ACK not received by iperf client?

I have an application that essentially consists of four components A, B, C, D. A and B are on the same machine - B and C are separate machines. Traffic is generated by an iperf client on A with a ...
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1answer
43 views

iptable rule and iftop command

Someone is flooding our server with UDP packets. I simply put iptable rule to block that IP. However, when I run iftop command I can see a huge traffic coming to my server. When i looked for iptables ...
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15 views

rsyslog tcp packets containing multiple log messages

I have rsyslog receiving logs over udp and then relaying them over tcp to a load balance (nginx) which passes them along to SIEM collectors. The setup looks like this: network devices/appliances ...
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1answer
18 views

socat udp packet forwarding with source address

I am trying to use socat (instead of iptables) for UDP port forwarding. I just need to redirect some traffic from UDP port 162 to 33162. I am using something like this: socat ...
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1answer
28 views

Can't change source IP address (to floating ip) for udp outgoing packages

I'm having trouble getting a cluster to work using pacemaker and corosync. Here is my hardware configuration: Network: 192.168.3.0/255.255.255.0 Gateway: 192.168.3.1 node1 (Ubuntu Server 12.04 x64) ...
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17 views

Can't stop the UDP packets [duplicate]

My datacenter has stopped my cloud server because my server is producing excessive UDP traffic. I have run: tcpdump -i eth0 udp and following is a sample set of log. 13:09:42.789583 IP ...
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23 views

Caching UDP packets with iptables

I have a server set up to forward all of its packets on a certain port to another host with the following command; iptables -t nat -A PREROUTING -p udp --dport PORT -j DNAT --to-destination IP:PORT ...
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1answer
23 views

heartbeat timeout error in tsunami deamon

I am trying to transfer a large file from server A to server B using tsunami. I am getting following error: Heartbeat timeout of 15 seconds reached, terminating transfer. And here are details: ...
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12 views

Something like Receive Segment Coalescing for UDP

The TechNet page on RSC states: RSC is defined only for TCP connections. RSC does not work with User Datagram Protocol (UDP) and other transport layer protocols. This is of course ...
16
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228 views

Vendor whitepaper says: 5Mpps no prob. I'm already hitting a wall at 120kpps. Where's the bottleneck?

HP's whitepaper on their QLogic (fka Broadcom) NetXtreme II adapters, which includes the specific NIC that I'm testing, states (page 7) that their small packet performance for packets up to 256 ...
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1answer
32 views

How does acting as an RDP host affect UDP visibility/routing?

This is an odd one. First, THIS IS NOT A NETWORKING ISSUE. This is an "rdp host behavior" that can be seen, from one persective, via the behavior of an RDP app. (see What happens to a Windows 7 ...
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1answer
78 views

Block an IP for UDP

I am under UDP flood attack. I used following protections to solve it: iptable IP ban: iptables -I INPUT -s 37.187.231.xxx -j DROP Tried another iptable syntax /sbin/iptables -I INPUT -i eth0 -s ...
8
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2answers
263 views

Extreme UDP packet loss at 300Mbit (14%), but TCP > 800Mbit w/o retransmits

I have a linux box I use as the iperf3 client, testing 2 identically equipped Windows 2012 R2 server boxes with Broadcom BCM5721, 1Gb adapters (2 ports, but only 1 used for the test). All machines are ...
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1answer
103 views

Make Asterisk to serve another subnet

I have server with Linux Ubuntu 12.04. It has two subnets - 192.168.0.1(eth0) and 192.168.1.1 (eth1). There is an Asterisk server (IP PBX) connected to first subnet, lets say it has IP address ...
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39 views

Linux kernel treating racoon's UDP socket as nonexistent

How can I figure out what's going on here? I've tried everything I know how to do short of adding printks or running a debugger on the kernel. I'm hoping somebody can spot something obvious that I've ...
12
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4answers
276 views

tcpdump increases udp performance

I'm running a set of load tests to determine the performance of the following setup: Node.js test suite (client) --> StatsD (server) --> Graphite (server) In short, the node.js test suite ...
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32 views

how to increase inter packet delay for multicast video packets

i have two embedded boards with Linux which stream (multicast) live video with 20Mbps rate. However when i connect both boards to a 100Mb switch ( 1G switch works fine) , video get's corrupted ...
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196 views

Fast Ethernet UDP optimize receive buffers

I have a Linux computer which must receive streaming data from several devices (up to 30 or so) during long terms. This computer is connected to a Fast Ethernet local area network (100 Mbps) where ...
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1answer
43 views

How does udp work when links en route have different speeds? [closed]

My understanding of UDP is that it is a best effort protocol. The data is simply sent and may or may not get there. If I am sending data from A to B using UDP over the Internet and the first link ...
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64 views

Multicast works only in promiscuous mode

I'm trying to receive MPEG-TS over UDP multicast transport in Arch Linux. So when I run ffprobe -i udp://@224.1.1.240:6000 it hangs forever with no result. Then I run tcpdump and it shows no ...
2
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1answer
75 views

How to setup routing for UDP in AWS instance

I'm new to AWS and I'm wondering if any one could provide a guild/link on how to go about setting up, what I'm guessing is VPC, so that I can send UDP packets to and from my instance via my public IP. ...
2
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1answer
53 views

Monitoring /proc/net/udp

I am interested in tracking changes in /proc/net/udp, particularly in the "drops" column. I want to know the the approximate time when a drop counter goes up. Also, if the socket gets destroyed, I ...
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38 views

RX errors when using jumbo packets

We have a device outputting high speed data over UDP connected directly to a processor (no switch). The processor is running CentOS 6.6. The connection is gigabit Ethernet. When we use packet sizes ...
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1answer
151 views

Why some iptables DNAT rules don't work until reboot?

My iptables DNAT rules don't work until reboot. If I reboot my server, all of the rules work. Desciption of the architecture : Tens of hosts (senders) send some UDP packets (one-way on a specific ...
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2answers
2k views

Load Balancing DNS Servers: UDP / TCP

I have been asked to rebuild our load balancing infrastructure in the data center. The original request was to load balance FTP servers. I tried doing that using the current load balancer (Piranha / ...
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1answer
72 views

Multicast and duplicate IP addresses

I've developed a Multicast UDP client/server application, which allows a user to remotely change the network configuration of devices belonging to the same multicast group. But what if a device was ...
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151 views

Piping device file over UDP with netcat

Hopefully this is the best Stack Exchange site for this - I think it's primarily a netcat question. I'm developing a custom data acquisition device. It can probably be best thought of as a fancy ...
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1answer
267 views

UDP reverse proxy on Linux [duplicate]

I have a dedicated server which hosts game servers, and is vulnerable to DDoS attacks. I want to get a DDoS-protected VPS to act as a reverse proxy for UDP. The dedicated server's IP address is ...
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119 views

Troubleshooting multicast on Ubuntu 14.04 server

I am troubleshooting an issue with multicast on an Ubuntu 14.04.1 LTS server. I have a simple client that subscribes to a multicast group and waits for data. The subscription is successful and shows ...
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1answer
202 views

Maximum size of empty UDP packet

I want to stuff data into a packet, but I want to make sure that the packet does not exceed 512 bytes, so I need to know what the initial size of a UDP packet is so I know how much data I can put into ...
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94 views

Does Ubuntu with Linux 3.5 having TX RX ring buffers or BQL

My linux uname -a command outputs: Linux Davinci001 3.5.0-23-generic #35~precise1-Ubuntu SMP Fri Jan 25 17:13:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux So, does NICs with this Ubuntu machine is ...
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1answer
102 views

Is Linux limiting my application's UDP transfers, and how can I see it?

I am currently developping two applications to work over a custom video streaming "protocol". Basically: The server captures video frames from a webcam, slices them into parts, and sends these parts ...
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1answer
68 views

Plain UDP shows up as STUN in Wireshark

I am sending 4 bytes of data over UDP upon request from another program. Sometimes the frame's protocol is identified as STUN in Wireshark, but I have no clue why. A ruby prototype of the ...
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114 views

Is ARP Connection oriented or connectionless?

Is ARP Connection oriented or connectionless? It uses TCP, but does that consider it connection oriented?
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1answer
68 views

Redirect packet that matches a pattern?

How can I route an incoming udp packet with iptables that matches a pattern like: 53 41 4D 50 5B 79 95 DB 61 1E 69 from public interface (vmbr0) and port 7777 to 192.168.0.1:7777?
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31 views

Cannot query UDP services

I run a couple UDP services, one including Teamspeak 3. Unfortunately, I am unable to query either of these UDP services (I cannot connect to the Teamspeak 3 server) besides the TCP based stuff, ...
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2answers
381 views

tcpdump truncates to 1472 bytes useful data in UDP packets during the capture

I am writing an application which work with network. To perform some tests I need to reproduce the flow which I had a day before. But at the same time it is not allowed to stop the current working ...
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1answer
117 views

How to drop first udp packet from a source with iptables?

As a defense against distributed udp flood, I need to drop first udp packet from a source and accept other than first packet. Does iptables has capability of doing this? If yes, how?
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2answers
141 views

Would UDP over VPN eliminate packet loss?

I am receiving a MPTS UDP stream from a remote location and I am experiencing packet loss. I would like to know if there's any way to eliminate this packet loss while still using the UDP protocol? I ...
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473 views

Linux: Reduce UDP Packets Error

I'm facing UDP packet receive errors (under Linux 'netstat -su' command). I have 10 x UDP processes running on Machine-A (RHEL 5.2) and each of them send 290-byte packet at 50 times per second to ...
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53 views

UDP multicast stream on win server 2k8 R2

so i have 3 mega PCs with win 2k8 installed on them having: 1st) 1 internal NIC and 1 external 2nd) 2 internal NIC and 2 external 3rd) 2 internal NIC and 4 external same stream put on any NIC on 1st ...
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2answers
61 views

Clients phone provider claiming high latency over UDP, how do I test?

A client of our uses a hosted phone solution for his 50 agent call centre. They use a hosted dialer who make the out going calls, once the connection is made the call is passed to my clients user ...
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2answers
129 views

TCP/UDP Small Package Size optimization [closed]

I currently have the problem, that when a LOT of RTP streams (>800) go to one server the max. speed is onlynabout 70-80 Mbit (on a Gigabit LAN - all Hardware components are Gigabit components) 130 ...
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83 views

How can I log and maybe even block IPs that send lots of incoming UDP traffic?

we run a voice / teamspeak server which receives legitmate traffic on port 9987 from many ips. Sometimes we get DDoSed. So people use single Servers and send 1-3 Gbits of UDP Floods to that port. This ...
2
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1answer
356 views

UDP Proxy with cloned packets

Having UDP messages sent from dynamic public IP periodically to public IP X:20000. Need a proxy that listens in IP X:20000, then forwards duplicate/clone packets to X:20001 and a different machine ...
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0answers
72 views

How to turn a UDP feed on and off?

I have a linux application that is sending a stream of UDP packets to a particular ip and port. I need a way of suppressing this packet stream so the packets never reach the network, with the ability ...
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38 views

Bonding connection or other techniques to improve UDP delivery

I have several VOIP servers linked by heavily loaded connections, and the voice quality gets pretty spotty at times. I have setup QoS to ensure upstream bandwidth is allocated favorably for VOIP, ...
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2answers
162 views

NAGIOS host availability test for host that can't be PINGed, won't talk to me, but can be traceroute'd

Part of my network estate has a fairly important dependency on a host whose availability is difficult to check. I have a number of hosts behind it, and my NAGIOS VPS provider occasionally has routing ...