Questions tagged [udp]
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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Convert plain TCP package into http request
I have an Apache server set up on port 80, and I receive data (text string) in plain TCP/UDP packets on port 8082.
I need my Apache server to receive these text strings for processing.
If I have ...
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TPROXY is not redirecting all traffic to a specified port
I'm writing a UDP transparent proxy in Rust, I'm using several crates
socket2 => Access to the creation of a RAW socket
nix::sys::socket => Access to all of the low level socket API calls
std::...
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A command to troubleshoot UDP traffic forwarding issues?
I've been setting up a UDP forwarding configuration to a load balancer in a private network in Azure with a colleague. The attempted setup was something like this:
There's the actual target UDP ...
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Can't see udp packets with nc command, works with tcpdump
I'm trying to capture UDP data using the nc (netcat) command but it doesn't output anything. What options/parameters do I need to pass to the nc command to get the output?
tcpdump does show the UDP ...
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Iptables duplicate/Mirror incoming UDP traffic from HOST1 to an external HOST2
I need an advice about the following scenario:
IoT devices are sending UDP packets to a 18.04 Ubuntu server environment (HOST1) on port 1234.
HOST1 processes the UDP packets as per the internal ...
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Iptables: limit mdns packet per second per ip
I have a network with a lot of MDNS (UDP 5353) traffic on it.
To avoid overloading my server, I limit globally the MDNS packets accepted by iptables with this rules:
iptables -A INPUT -i eth2 -p udp --...
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Bad address translation in Kubernetes UDP service by kube-proxy with iptables
For educational purposes, I made myself a Kubernetes cluster according to Kubernetes the Hard Way guide - except I did it on my own set of local VMs rather than using Google Cloud.
Everything seemed ...
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Ubuntu Network: Allow UDP connection to Port B if a UDP connection was established to Port A before
I want to setup an IPv4 firewall for UDP connections to port :7777 with the following rules:
By default block all connections to UDP Port :7777.
Allow only whitelisted IPs connections to UDP Port :...
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UDP Port Forwarding
I got 2 servers Named A and B, both are in different data centers and just have internet access.
I need the incoming UDP connections to a particular port on server A to be forwarded to a specific port ...
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Redirect incoming UDP traffic to a local ip adress (iptables?)
tcpdump works as expected on my machine.
tcpdump -i enx00e04c04009e -Uw - | tcpdump -en -r - vlan 201
17:52:51.447340 04:01:30:00:00:16 > 03:00:03:00:04:00, ethertype 802.1Q (0x8100), length 66: ...
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.io auth. NS refuses UDP response to dnsviz.net – why shouldn’t I, too?
Seriously, say, I block (return, not drop of course) UDP :53 in to my authoritative nameserver. Resolvers will fall back to TCP and I won’t need any rate limiting against spoofed source IPs. Because ...
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Error in udp reverse proxy with nginx stream failed (90: Message too long)
I want to proxy UDP traffic with nginx. nginx doesn't complain about the configuration. The client connects halfway (it says it can reach the end server), but the connection gets stuck and eventually ...
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IP fragments are not reassembled due to packet loss in Linux
I have been working with a device that sends heavy TCP/IP traffic.
I'm trying to capture those packets in my Linux machine (Ubuntu 22.04.2 LTS) with Python programming language.
But, most of the time ...
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iPerf3 UDP TX/RX bytes mismatch but no loss
I am not able to interpret the following iPerf3 results.
Client:
iperf3 -c SERVER -u -R -b 350M
Connecting to host SERVER, port 5201
Reverse mode, remote host SERVER is sending
[ 5] local CLIENT ...
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Interpret Iperf3 results for bidirectional UDP Test
I am trying to make sense of the raw logs of an iperf3 UDP bidIrectional test.
Here are the iperf3 client logs:
[ ID][Role] Interval Transfer Bitrate Jitter Lost/Total ...
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Rocky Linux 8 Blocking SIP traffic
I am having trouble with Rocky Linux blocking SIP traffic from an external LAN.
If I send a SIP message from external LAN, it reaches the server but the message doesnt get passed to the application.
...
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Nginx UDP proxy shared connection is busy
We are proxying UDP packets for a game server through a Nginx reverse proxy. Clients timeout very often because the Nginx can't handle the requests. Initially it works flawlessly, but when more ...
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using putty and socat to run rust server behind firewalls
i want to run a publicly accessible Rust server on a windows machine behind some routers and firewalls. the idea is tunneling the local server ports to a public machine where they are accessable: rust ...
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UDP Nginx proxy timeout issue (Shared connection busy)
I have setup a TCP/UDP proxy with nginx on multiple servers. Nginx is struggling to handle some client which causes timeouts for the users.
Here is the proxy setup
stream {
upstream backend {
...
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Is there a way to exclude a network interface from being bound via INADDR_ANY?
In network programming, it's common to pass INADDR_ANY (or IN6ADDR_ANY) as part of the second argument to bind(), telling the networking stack that you want the socket to receive connections/traffic ...
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Kubernetes - NodePort with persistent connections
I am running a multi-node cluster of UDP game servers that need to be accessible to the player on a single domain name and port, i.e. example.com:19132. The game runs in a way that requires a series ...
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tcp syn is blocked, cant make a connection
so this is my current setup of openvpn+stunnel
user>>internal-server-A(as stunnel client)>>main-out-of-country-server(running openvpn and stunnel as server)
it worked fine in a restricted ...
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SIP Websocket to UDP proxy server
There is an ATS provider with SIP phones. It provides phones via UDP, as I understand, giving sip server, login and password for each internal call-line.
I want to write a site with browser calls ...
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How can I print the payload received with ncat?
I'm creating an UDP server with the following command:
ncat -ulk -p 3333 -c "echo asd" -vv
It does receive connections and answers to them correctly, but it doesn't print the UDP payload ...
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Netcat UDP server is not sending a response
I'm trying to get OpenBSD netcat to listen to UDP connections on a particular port (3333) and interface (10.42.0.1) and send a fixed response. To achieve this I do:
echo "asd" | nc -k -u -l -...
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iptables bidirectional nat udp configuration for multiple sources
I have the following setup, all udp packets:
client (42.123.124.125) -> (42.123.0.125) nat_server (192.168.2.2) -> (192.168.2.5) udp_service
nat_server has to receive incoming udp from client ...
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Piping data from ethernet to serial and back to ethernet doesn't reach destination
CONCEPT VISUALIZED
I'm trying to establish a bidirectional communication where ethernet UDP packets enter a linux system (suppose a Raspberry pi) from eth0 interface and piped into the UART hardware ...
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Forward UDP broadcasts to another IP
I receive UDP broadcast packets on wlan0 on my Raspberry Pi which I'd like to forward to my desktop for analysis via eth0.
I'm running a modified WiFi firmware on a raspberrypi which sends UDP packets ...
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Port forwarding UDP10000
Sorry for my poor english...
here is my network:
Network
I try to setting up a jitsi meet server behind my two Firewalls and the reverse proxy, but i meet a problem.
I can access to video and sound ...
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OVH VPS as a reverse proxy - UDP DDOS attack causing invalid packets
I am using VPS from OVH as a reverse proxy to protect my dedicated server from DDOS attacks. OVH has very good DDOS protection. My dedicated server hasn't.
Everything works good, I am attacking my VPS ...
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SOCAT command for UDP relay using single port
I am using SOCAT linux command for relaying udp packets. Currently I am simulating using VMware.
I used sudo socat -T 10 UDP4-LISTEN:132,reuseaddr,fork UDP4:192.168.11.130:130,bind=192.168.11.131:133 ...
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Returns of UDP packets are discarded
I use High avaibility pfSense 2.6.0 cluster and I strange behavior with UDP when use Discord voice channel.
In fact, discord voice channel display "No route" and traffic analysis paquets ...
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iptable's ip forwarding results in weird behaviour
My target is simple : Build a high volume, fast, low latency soft switch using IP forwarding. I have a server test 'Server' and 2 test clients : 'Client1' & 'Client2'.
'Client1:c1' is sending udp ...
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iptables: can't drop incoming DNS responses containing a specific IP address
I want to drop incoming DNS responses that contain 10.10.34.35. How can I do that?
I tried to it this way:
iptables -I INPUT -m udp -p udp --sport 53 -m string --algo kmp --hex-string '|31 30 02 31 30 ...
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Too much download bandwidth on nginx process
I rent dedicated server from company and I noticed it is using too much download bandwidth constantly on nginx process even with low traffic on non peak hours. I checked with tcpdump and I saw those
...
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Double Proxy: IPSec to Server1 then SSH to Server2
What I'm trying to achieve:
(Clients)<IPSec Xauth PSK>(Server 1)<SSH-based SOCKS5>(Server 2) --> Free Internet
How is that possible for both UDP and TCP traffics?
What I've done:
I ran ...
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How to test UDP echo using nping
I need to test performance of UDP echo server application.
I use nping to generate traffic however nping always reports 100% packet loss no matter to which port the server returns the echo packets.
...
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Load Balancing DNS Servers UDP on HAProxy
I have read quite a few articles about UDP load balancing. I didn't find helpful information. (find a few answers which are quite old info I guess)
My question is does HAProxy support the UDP? If Yes ...
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eBPF program appears to duplicate packets sometimes
I am trying to understand behaviour of eBPF/XDP under Linux. I have 2 machines connected by an isolated 100gE network. On one I run a udp sender application which is configured to send 10M packets of ...
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How does linux / netfilter / iptables "know" if a packet is meant for itself for to be forwarded
I have setup an ubuntu box as a router manually , using iptables + NAT.
But I was wondering, how does the "middle-router" know if the packet is meant for it or to be forwarded?
I tested this ...
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Range of Normal Usage for Domain Controller's LDAP Ping
I'm a security research studying CLDAP as a vector for UDP reflection attacks, a from of Denial of Service. I'm not a MS Server expert, so I want to sure up my understanding of the context of the ...
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how to upload a udp stream to AWS
I have a stream that only has udp protocol and I need to upload it to my AWS cloud server. Is it possible to send udp to the server if I don't have the stream in the local network of the AWS server? ...
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traceroute shows stars but netcat reaches the port
I have several (virtual) machines with Centos 7 in the same subnet with several instances of my app running on each of them. I need to test how the apps can reach each other by UDP.
I'm trying to ...
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How To Force User Agents To Use Later Available Version of HTTP?
A OpenLiteSpeed Web Server is running on AlmaLinux 8.
HTTP/1.1, HTTP/2 and HTTP/3 QUIC are enabled.
80/tcp, 443/tcp and 443/udp ports are open publicly and permanently.
The server is sending the below ...
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How to set specific broadcast IP address on Windows
Problem:
I have a machine Sender, that sends packages to a certain IP address in a local network. I have also machines A, B, C, etc, connected to the same local network. I want these machines to ...
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DNSMASQ-TFTP failed sending file for PXE boot
2 month ago my PXE installation worked perfectly, now it can't send the file grubx64.efi to begin the PXE installation.
juil. 08 08:03:05 install-server.my.domain dnsmasq[5913]: started, version 2.79 ...
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DNS lookup failing even though tcpdump shows that nameserver has responded
DNS lookup on some of my EC2 instances have been failing intermittently. A reboot resolves the problem but it goes back to the same fail-state after a few hours (or after a few days), and remains in ...
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How can I maximize UDP Packet Size?
I am a gamer. I play UDP-based games. I want to increase the packet size. I know the UDP packet size is 1024 but i want to increase this packet size even more. I want to increase the performance I get ...
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UDP broadcast with nc not received (Ubuntu)
I'm trying to understand UDP broadcasting, and running into some trouble.
1 - Running a server like this
nc.traditional -l -u 10.0.0.253 -p 65001
2 - Sending stuff from the client like this - on the ...
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Could someone please explain the difference between these expressions
drop proto tcp and not (dst port 80)
pass proto tcp and dst port 80
Is there a difference between them?
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