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Questions tagged [multicast]

To be used with questions about network multi-casting in general.

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what does `IgnoredMulti` statistic for Udp in debian linux mean?

I have a Ubuntu machine that is receiving UDP packets by joining a multicast group, occasionally we are getting UDP packet drops. when I am trying to monitor using netstat -s I get the following ...
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EADDRNOTAVAIL when dropping IGMPv2 membership and forcefully sending rejoins on interval

I have a case where I want to send a IGMP membership report every N interval. Currently I have one socket that uses setsockopt to join and maintain that membership via the kernel. I have also set up ...
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1 answer
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Centos8 does not respond to IGMP v2 membership queries

In troubleshooting a general issue why a Centos 8 box doesn't receive multicast data after sending a JOIN, analyzing with wireshark also shows the Centos box not responding to IGMP v2 membership ...
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IGMP v3 JOIN sent but no traffic from switch

I'm trying to join an IGMP multicast stream from a Centos 8 machine but after sending a JOIN, there is no traffic coming from the switch. Simple connection: MUX <-----------> cisco3850 <------...
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  • 377
3 votes
2 answers
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How to set preferred IPv6 interface

I have a program that sends multicast traffic via IPv6. It sends traffic out of the default network interface. It works fine normally (traffic goes out eth0) however if I have Docker loaded, then it ...
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2 votes
1 answer
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How to check if someone is streaming RTP over a specific Multicast address?

Let's say we have ubuntu machine A with ip 192.168.0.20 and ubuntu machine B with ip 192.168.0.21 in same network. How can I check if machine A is streaming RTP to a multicast address and port for ...
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1 vote
1 answer
250 views

netcat producing EINVAL when sending to UDP IPv6 multicast

I'm using netcat on Fedora to test an IPv6 UDP multi-cast address. The command is echo hi | nc -6 -u ff02::777:777:777 7777 netcat responds, "Invalid argument." Running strace yields ...
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1 answer
176 views

How can i create a multicast group and send a message to it?

I want to create a multicast group with 3 computers then ping them all, how is it done in the Linux CLI?
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systemd-networkd multicast route removed when no carrier

We have a gateway product running Ubuntu 20.04 LTS. It has two network interfaces (WAN/LAN) configured using systemd-networkd. We use multicast messages to communicate to thousands of IoT devices ...
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Converting an add-rule to a service for firewalld

I am having a hard time creating the following lines for multicasting into a service in firewalld. firewall-cmd --permanent --add-port=49152-65532/udp firewall-cmd --permanent --direct --add-rule ipv4 ...
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1 answer
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incoming UDP multicast stream stops after fixed time on macOS

My ISP provides IPTV feature, stream example: udp://@239.255.2.97:5500. I'd like to watch IPTV on macOS, so I used VLC. Initially, IPTV didn't work at all. At first I thought that it's locked to ISP's ...
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How to copy large files via network to multiple Linux PC at once?

I have 15 Linux PC and I need to install two virtual machine(Windows 10 and Ubuntu) in every one of these PCs. I decided to install these two machine in one PC and copy virtual machine files to ...
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Linux: UDP "multiplexer" inside kernel

I have an application with very high performance requirements and the following job: There is incoming UDP traffic on port 1234. The packets have as fast as possible to be sent to hosts H1, H2, ... Hn ...
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1 vote
1 answer
197 views

Multicast route not linking to userspace

Ok So I have a user space application that needs to get data from multicast traffic, however I cannot seem to get the traffic out of kernel space and into userspace where the application can utilize ...
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9 votes
5 answers
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How to install Linux on multiple PCs at once?

I need to install Linux OS on 30 PCs. Is there any way to install from one ISO image with multicast or something like WDS in Microsoft? I have a Ethernet connection with speed of 100Mb so installing ...
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1 answer
2k views

how to test multicast with socat on one machine

I'm a linux beginner and trying to test multicast with socat on Ubuntu which works. A bit "too well" actually (or I'm misunderstanding something fundamental) my network looks that (ifconfig, ...
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2 answers
226 views

How does multicast routing work on the internet?

For a LAN, it is effectively several additional layers of filters on hardware/software, maybe including switch(IGMP snooping)/NIC/kernel stack, etc. Otherwise it is similar to broadcast. I think I can ...
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Can UDP multicast listening socket receive unicast packet, OR, can UDP unicast socket receive multicast packet, on Linux IPv4 stack?

My understanding is this, if a socket does not bind local address(or binds to INADDR_ANY), and does not call connect() to set remote address/port, then there is no way to prevent unicast packets to be ...
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0 answers
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Tunnelling IP Multicast traffic between two residential networks or machines

The Ableton Link music synchronization service operates by broadcasting and receiving messages via an IPv4 multicast group in the "Ad-Hoc 2" address block. In order to use the protocol to synchronize ...
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3 votes
0 answers
695 views

Debian ignores second multicast packet

I have a home local network with several devices. One of the devices is sending multicast packets with information about some events (smart home). It works well - I've tried to launch Multicast Tester ...
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465 views

Setting up multicast between two apps on same computer

I have two Java apps running on the same computer. Each one uses the IP address of the computer (the IP on the enpXXX interface). App1 sends a packet to App2 using multicast, but it doesn't seem to ...
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1 answer
481 views

Multicast packets being dropped at IP layer?

External multicast data is being received by machine #1 and forwarded to machine #2. On machine #2 I can see the multicast packets being received when I use tcpdump, ethtool and netstat -i (ethernet ...
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1 answer
420 views

network behaviour with tcpdump

We are developing communication interface converter which is running Linux. The unit may receive unicast or multicast IP and converts it to some other physical layer. On the other hand, the unit ...
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4 votes
2 answers
3k views

Multicast routing using netplan

Trying to setup multicast route to interface in Ubuntu 18.04.2 Netplan's syntax does not allow something like: routes: - to: 224.0.0.0/4 dev: eno1 this config does not work: addresses: - 192....
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1 vote
1 answer
339 views

IGMPv3 Source Filtering Configuration

I know that multicast addresses are being kept in /proc/net/igmp. Where is the configuration for v3 source filter being kept? Please note that I do not wish to inspect actual IGMP packets, I wish to ...
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1 vote
2 answers
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install smcroute in Linux

How do I install smcroute in Ubuntu 16.04? If I try to install using apt-get, I am not finding the commands "smcrouted" and "smcroutectl" in bash. Also, the GitHub page asks to configure the kernel to ...
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7 votes
0 answers
458 views

Multicast ICMPv6 comes back with conntrack state invalid

I was playing arround with the Multicast feature of IPv6. $ ping ff02::2%wlp3s0 This should normally result in an echo-reply from all the routers on your local network segment (Wikipedia - IPv6). So ...
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1 vote
0 answers
117 views

Strange behaviour sending IGMP on multi IP address for interface

I'd be glad to have some info/clue on the behavior in the followings situation: There are eth0 with IP address 10.10.10.10 and eth0:1 with IP address 20.20.20.20. IGMP join and leave shall be send ...
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1k views

How to setup default source interface for multicast?

There is a server 172.16.0.50 with udpxy. It converts multicast video to http unicast streaming to "R2" router clients. There is igmp-proxy setup on "R1". My aim is remove igmp-proxy and link between ...
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1 vote
1 answer
1k views

Why would properly VLAN tagged multicast traffic not arrive on the tagged interface?

I'm working with an application that sends multicast traffic between a client and server. This traffic is sent via multicast. The client and server are both using VLAN interfaces, and need to ...
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2 votes
0 answers
926 views

PulseAudio RTP Multicast - how to synchronize audio on all receivers?

I am streaming music from a single controlling PC ("sender") to multiple PCs (receivers) on my LAN as described here: https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Network/#...
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2 votes
1 answer
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multicast traffic is able to poke a hole into the netfilter connection tracking system

I have an IPTV solution at home where the ISP sends me hundreds of large UDP datagrams per second from 10.4.4.5 port 10 to 239.3.5.3 port 10, i.e. it is using multicast. My current iptables ...
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1 vote
1 answer
703 views

Linux VRF and Multicast IP

I am attempting to use VRFs in Xubuntu 18.04, but I'm not having much luck when it comes to multicast IP addresses. I have been using https://www.kernel.org/doc/Documentation/networking/vrf.txt as a ...
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  • 111
0 votes
1 answer
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How to setup multicast for this network?

I have a Network like this at my home. # ip route show default via 192.168.0.1 dev enp1s0 192.168.0.0/24 dev enp1s0 proto kernel scope link src 192.168.0.110 192.168.1.0/24 dev enp3s0 proto ...
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1 vote
1 answer
623 views

Packet delimiter in netcat source file

Is there a delimiter or some way of telling netcat how many bytes to send per packet from a file? Invoking netcat multiple times in a script is not acceptable as I need to send them out as fast as ...
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  • 111
0 votes
1 answer
2k views

Accessing qemu multicast networks (from Docker containers)

QEMU allows to connect different VMs by using a virtual network based on a common multicast address by specifying -netdev socket,mcast=230.0.0.1:1234 on startup. This way I can easily connect ...
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1 vote
0 answers
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multicast_to_unicast with hostapd on RPi

I'm trying to use hostapd's multicast_to_unicast feature. The AP is working fine, but I get this error: nl80211: multicast to unicast not supported on interface wlan0 I'm on Raspbian with next ...
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1 vote
0 answers
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Identify application that created a certain IGMP join request?

Is there a way to find from which application a certain "Group Record" came from in an IGMPv3 packet? We are trying to figure the application that added the IGMP request to include source as local ...
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1 vote
0 answers
350 views

Example setup for zita-njbridge in multicast mode?

Do you have a working zita-njbridge triplet of command lines (one n2j, two j2n) proven to run in multicast mode, which you might share? I'd like to study a working example, to compare to my special ...
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0 votes
2 answers
1k views

muticast issue between two ubuntu machines

I have two ubuntu 16.04 machines (machine A and B) wich are connected by network cable. Machine A is creating multicasts. The multicasts do not reach machine B. Does anyone know, what the reason for ...
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1 vote
0 answers
470 views

Reading MLDv2 queries using an IPv6 socket

I have mrd6 installed on my raspberry pi. It registers with a local interface (tun0) and periodically transmits MLDv2 queries over it. According to [RFC3810], MLDv2 message types are a subset of ...
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  • 111
4 votes
2 answers
2k views

Connecting two clients on different physical interfaces using smcroute

I am very new to networking. I have two clients connected on two different physical interfaces which has upnp running on them. I want to add both of them to the same multicast group, so that they both ...
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  • 193
4 votes
1 answer
811 views

Responses from multicast 255.255.255.255

On one particular box, i cannot get responses to broadcasted messages to (255.255.255.255). For example Sending DHCPDISCOVER DHCPREQUEST on wlan0 to 255.255.255.255 And see even responses from ...
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  • 161
3 votes
1 answer
3k views

Is Pulseaudio able to receive RTP Multicast from any source?

Been attempting to get Pulseaudio to receive an RTP stream from VLC. I can get it to receive a TCP audio stream no problem - the pi running Pulse is receiving the multicast data as expected, but when ...
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5 votes
2 answers
15k views

How do I forward multicast traffic between 2 different LANs using iptables?

Goal: Need lmc or "LAN Messenger" to work on 2 lans separated by a Linux gateway using iptables. Information: Must be this program "LAN Messenger". Lmc uses multicast address 239.255.100.100:50000 ...
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0 votes
1 answer
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do mDNS and LLMNR queries use the same format as tcp DNS?

mDNS clients send queries to 224.0.0.251:5353 LLMNR clients send queries to 224.0.0.252:5355 Is their packets format the same as good old fashioned tcp dns ? Let suppose I want to resolve the ...
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3 votes
0 answers
212 views

using IPv6 Multicast to push a file

I would like to push a file over the network once to reach multiple linux hosts over IPv6 using multicast. (I think, that's the best way) How can I get my file pushed over IPv6 to multiple systems? I ...
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3 votes
0 answers
649 views

Avahi seems to stop publishing/refreshing services after a while

Firstable, I looked up to several Q/A, i can ensure that the following points are fullfiled: IGMP snooping isn't filtered by switch/router. Bonjour services (mDNSResponder.exe) is granted and allowed ...
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  • 31
3 votes
1 answer
5k views

Cannot disable multicast in linux

Environment: Two servers connected through a router, both running Ubuntu 16.04 I use the following commands to disable multicast: ifconfig eno1 -multicast or ip link set eno1 multicast off And ...
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2 votes
2 answers
1k views

Continuous multicast traffic from my router

I'm using an iptables firewall on my local Linux server. The log tells me that there is a continuous multicast on the network by my router (Fritz box). Is this a normal behaviour. Should I allow this ...
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