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

0
votes
0answers
81 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 ...
1
vote
1answer
707 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 ...
1
vote
2answers
238 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) ...
0
votes
0answers
20 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 ...
0
votes
1answer
91 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 ...
-1
votes
1answer
184 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: ...
16
votes
1answer
286 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 ...
0
votes
1answer
48 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 ...
1
vote
1answer
1k 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
votes
2answers
5k 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 ...
0
votes
1answer
307 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 ...
12
votes
4answers
529 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 ...
0
votes
0answers
536 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 ...
-1
votes
1answer
49 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 ...
1
vote
0answers
221 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
votes
1answer
289 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
votes
1answer
107 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 ...
0
votes
0answers
58 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 ...
1
vote
1answer
1k 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 ...
5
votes
2answers
5k 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 / ...
-1
votes
1answer
149 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 ...
0
votes
0answers
321 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 ...
-1
votes
1answer
924 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 ...
1
vote
1answer
359 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 ...
0
votes
0answers
183 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 ...
2
votes
1answer
231 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 ...
0
votes
1answer
196 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 ...
-1
votes
1answer
239 views

Is ARP Connection oriented or connectionless?

Is ARP Connection oriented or connectionless? It uses TCP, but does that consider it connection oriented?
1
vote
1answer
101 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?
3
votes
2answers
778 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 ...
0
votes
1answer
193 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?
0
votes
2answers
287 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 ...
0
votes
0answers
1k 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 ...
1
vote
2answers
112 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 ...
-1
votes
2answers
282 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 ...
0
votes
0answers
106 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
votes
1answer
722 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 ...
0
votes
0answers
92 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 ...
0
votes
2answers
361 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 ...
1
vote
1answer
528 views

Netcat UDP File Transfer Between Two Servers Times Out?

I'm testing file transfer speeds between two Red Hat servers that are connected to the same switch within the data center and I decided to use netcat to eliminate protocol overhead as much as ...
0
votes
2answers
2k views

lots of UDP_IN Blocked errors

Since I have reinstalled my OS, I'm getting lots of UDP_IN Blocked errors in my messages log. Can anyone kindly explain what the error say exactly and what I can do to get rid of this error. Aug 8 ...
0
votes
1answer
555 views

UDP packet loss cause

I have two machines connected to the same LAN and multicasting UDP streams at rate of about 30Mbps. Analyzers often show packet losses on one machine, but never on another. What could be the reasons ...
-1
votes
2answers
208 views

UDP Packet drop? [closed]

Multicast packet got drop between the server, multicast work on udp which unreliable so drop packet is expected Question: is their a way or utility available to capture udp packet at os kernel ...
3
votes
1answer
735 views

Difference between /dev/udp and netcat

I have a syslog server listening on localhost:514 as UDP and would like to write messages to it on that port. (Using Ubuntu 14.04) If I run either of these commands this from bash it prints the date ...
2
votes
0answers
30 views

Are DNS server responses categorized as “ESTABLISHED” by iptables? If so, why? [duplicate]

CentOS 5.x I'm trying to confirm which specific rule in my iptables config is allowing return UDP traffic from my DNS server. I THINK, it's this one: -A RH-Firewall-1-INPUT -m state --state ...
0
votes
1answer
838 views

Set udp packet size limit

I have a CentOS server with a JAVA application that receive UDP data packets, it works all OK until the packet is bigger than 584 bytes, I read something about and seems to be a limit of UDP protocol. ...
1
vote
0answers
346 views

Firewall rejecting UDP “connections”?

I have a server that is aggregating logs from various other servers. It mostly works great, however from time-to-time (right after a reboot, but not all reboots) it will decide that various UDP ...
2
votes
2answers
333 views

tcpreplay throughput on eth0 well below (iperf confirmed) max

I'm trying to replay captured UDP multicast packets at a rate of a couple of hundreds of Mbps, but it maxes out at about 86 Mbps. (For some strange reason, at other times during the day it ...
2
votes
1answer
97 views

How to see log of apps taking specific port over period of time on Windows?

How can I see for specific time period, which app had bound some specific port in Windows? I am auto-starting my app with windows and I am bounding port 1200 as UDP packet receiver, but sometimes my ...
8
votes
1answer
2k views

mosh-like port forwarding

This is on linux, connecting to linux servers: I love mosh, but it doesn't support port forwarding, and likely won't for a while since it's been almost a year now and it hasn't happened yet. port ...