In computer networking, multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source. Copies are automatically created in other network elements, such as routers, but only when the topology of the network requires ...

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ntp multicast address

A silly question probably, but guess I need to ask. If I've got four centos boxes that are acting as ntpd multicast servers, will the multicast address configured in each box's ntp.conf all be the ...
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2answers
3k views

multicast tcpdump and subscriptions

From the multicast howto: IP_ADD_MEMBERSHIP. Recall that you need to tell the kernel which multicast groups you are interested in. If no process is interested in a group, packets ...
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1answer
387 views

How to send multicast traffic from one vlan to 100-500 other

In addition to prev question How to share multicast traffic to many vlans I recieve answer that solution for my task is mrouted on my freebsd router. But for now i see this problems: mrouted ...
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1answer
700 views

Multicast with wifi access points

Using 2 consumer grade access points what is the behavior of when multicast packets are sent between them. Consider -> AP1 -> AP2 (Note that AP1 & AP2 are connected over the LAN ports to the ...
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1answer
496 views

How to share multicast traffic to many vlans

I have linux computer , this computer connected with entire my network via zyxel gs-2200. In this zyxel also connected router with 500 vlans, one by client. On linux computer i have vlc program ...
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2answers
1k views

virtualization with multicast receive

I need a virtualization solution with the following properties: guest OSes can receive multicast traffic from the host machine. some services running on the guest OS (eg: port 80) can be port ...
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1answer
2k views

iperf max udp multicast performance peaking at 10Mbit/s?

I'm trying to test UDP multicast throughput via iperf but it seems like it's not sending more than 10Mbit/s from my dev machine: C:\> iperf -c 224.0.166.111 -u -T 1 -t 100 -i 1 -b 1000000000 ...
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0answers
796 views

Problems with multicast under Mac OSX Lion

We have been developing our Java applications under OSX for some time. Since switching to OSX Lion (version 10.7.1 now), we see sporadic issues around multicast packets going into the bit bucket and ...
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1answer
72 views

Can I use routes to influence which interface address multicast listeners use?

I have a server with multiple NICs on it. Each NIC is plugged into a different, isolated network that is serving multicast traffic. I have a program that listens to the multicast traffic on each of ...
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4answers
642 views

Is there a good way to keep IPv6 multicast packets off WiFi?

I work on a product that consists of a number of headless Linux boxes that work together as a cluster. These boxes synchronize their state with each other by sending proprietary-format link-local IPv6 ...
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0answers
2k views

UDP Multicast not working without promisc. Already tried rp_filter=0

I'm having issues with multicast traffic in Ubuntu Maverick. It only appears to work when the card is in promisc mode (i.e. if I set it manually, or use a tool such as tcpdump). Adding multicast ...
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2answers
320 views

multicasting in different networks in java

I'm writing a code to work through sockets in java. I've created a multicast group to which anybody can join on the LAN. But the LAN has many different networks, operated by a router, and the ...
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4answers
1k views

Capturing multicast data with Wireshark with IGMP Snooping Enabled at the switch

I am trying to capture multicast traffic via Wireshark (actually TShark), however the switch has IGMP snooping enabled and will only send Multicast traffic on the ports that have an active IGMP ...
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1answer
1k views

windws server 2008 udp multicast performance problem

I encounter a strange performance problem on 2008 R2 Enterprise SP1. Here is the setup: Many processes listening to distinct Multicast UDP streams (5 multicasts listen by process) bound on a single ...
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0answers
2k views

Can't get multicast to work (iperf)

I have some problems to get SLP (service location protocol; I play around with the OpenSLP implementation) to work. It uses multicast on 239.255.255.253, port 427. To narrow down the problem I decided ...
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4answers
12k views

How can I test Multicast UDP connectivity between two servers?

I have a two servers on the same subnet. I have an application installed which uses Multicast UDP to propagate events between the servers and keep them in sync. This does not seem to be happening, ...
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0answers
537 views

Multicast Packets do not Reach all VPN Clients

I am trying to setup a PPTP VPN using RRAS on Server 2008 R2. I've got RRAS setup and working, and clients can connect to it using Windows XP or Windows 7 (my two target platforms.) However, my ...
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1answer
544 views

NLB Traffic Stops on all nodes when a single node is rebooted

We had a 2 node NLB cluster running IIS websites on virtual machines. Both nodes were online, the balancer functioned exactly as expected, (if traffic is 50/50 balanced, and you stop or drainstop a ...
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1answer
2k views

Multicast hostname lookups on OSX

I have a problem with hostname lookups on my OSX computer. According to Apple's HK3473 document it says for v10.6: Host names that contain only one label in addition to local, for example ...
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3answers
25k views

What is the difference between unicast, anycast, broadcast and multicast traffic?

I have never had the privilege of working in an environment that required complicated routing or if it did require it, it was handled upstream of me. I've always used very simple static routing ...
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2answers
3k views

How managed switches handle Broadcast Multicast and Unicast?

Under typical scenarios, a network switch needs to handle broadcast, multicast and unicast messages at the same time. I'd like to understand On a typical managed switch (1Gb Ethernet/10Gb Ethernet), ...
9
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1answer
370 views

Simple Multicast Design

In order to support desktop imaging requirements I need to correct the multicast design on an existing network, but am not well versed in this subject. The diagram below gives a basic example of the ...
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0answers
518 views

Multicast Default Interface - upgrade to RH5.5

I have upgraded a server from RH4 -> RH5.5 and we have an interesting issue with multicast. we have multiple NICS on the server, we want the bond0 to default as the default interface. adding route ...
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1answer
6k views

How do I know if IP Multicasting is enabled on my network in Windows?

How do I know if IP Multicasting is enabled on my network? It is same question as above but for windows.
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2answers
358 views

Multicast IP Addresses

I posted this on StackOverflow and was told it might be more appropriate here. I'm having trouble understanding how multicast addresses work. First off, is it true that if I have N clients or peers ...
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4answers
4k views

Unicast to multicast via iptables

Note: While there is an accepted answer now, it is only part; check the final iptables rule below. I'm receiving a unicast RTP stream on one interface and wish to send it out via multicast on a ...
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2answers
639 views

looking for multicast traffic

We have a j2ee webapp on tomcat which is using ehcache with multicast discovery. Except it's not discovering anything. There appears to to be no multicast traffic visible on the network but we're a ...
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2answers
773 views

In what kind of environment multicast is not preferred?

While reading a product documentation I came across a line in which they say product supports TCP communication in environments where multicast is not available or preferred. Why would a company ...
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1answer
1k views

Stateful matching of multicast responses in iptables

A central part of my firewall configuration is: -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT It seems that RELATED does not work for multicast responses: when the host sends to a ...
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1answer
225 views

SNMP OID to get multicast bytes

Right now I can only find oid for ifInMulticastPkts and ifOutMulticastPkts, but there is no bytes information. Can anyone know about this? thanks in advance.
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1answer
1k views

Cisco 3560+ipservices — IGMP snooping issue with TTL=1

I've got a C3560 with Enhanced (IPSERVICES) image, routing multicast between its VLANs with no external multicast router. It's serving a test environment where developers may generate multicast ...
2
votes
1answer
829 views

Lot of Multicast traffic on LAN

Recently the whole network at work is being hit by multicast traffic originating on the LAN itself. I did some investigating and the service which seems to be responsible is ws-discovery. I have ...
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1answer
829 views

How do I enable multicast routing in Windows XP

I have successfully set up a Windows XP machine as an IPv6 router using netsh, that is, it announces prefixes and forwards packets on two interfaces, as verified by pinging. Now I'd like to forward ...
0
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1answer
474 views

Multiple network interfaces and UDP packets distribution

I have a Linux server with 2 1Gb network interfaces eth1 and eth2. If I start 2 clients listening to the same multicast address and each client connects through a different NIC (say client 1 listens ...
0
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1answer
402 views

Multicast NAT on Juniper router

I am trying to do source NAT on a J-series router (junos 9.2). I have two separate NAT rules setup (using security policies + source-nat interface). One is for regular unicast TCP connections and the ...
2
votes
1answer
900 views

openSUSE 11.3 multicast IGMP v2 works on one vlan, but not the other vlan

I have a server running openSUSE 11.3, with vlan5 and vlan40 configured on eth7. I want to join two multicast IGMP v2 groups, one on vlan5 and one on vlan40. When I send out the IGMP v2 Membership ...
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3answers
3k views

Basic multicast network performance problems

I've been using mpong from 29west's mtools package to get some basic idea of multicast latency across various Cisco switches: 1Gb 2960G, 10Gb 4900M and 10Gb Nexus N5548P. The 1Gb is just for ...
2
votes
4answers
620 views

Should a small company block multicast on their network?

Currently, the firewall at a small company is blocking multicast on their network. Should they continue to block multicast? Are there security concerns to unblocking it? Are there benefits to ...
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5answers
17k views

Tools to test multicast routing

I am looking for a good simple tool that runs on a standard OS (Windows or Linux) that I can used to test that multicast is being passed properly by a router. I have been asked by a client to enable ...
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2answers
2k views

Multicast over SSH

I have two LANs: 10.x.x.x and 192.x.x.x. On each LAN I have a Linux machine (10.x.x.5 and 192.x.x.5) but they are not routers. I can open ssh from 192.x.x.5 to 10.x.x.5. There are multicast udp ...
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1answer
9k views

How do I add a multicast route in Windows 7?

I have 2 interfaces on my desktop: one in a multicast enabled vlan, that has access to some udp streams, but otherwise unrouted, and one with internet access, but no multicast. If only the multicast ...
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2answers
406 views

Multicasting for WDS

I want to install a Windows 7 image on 40-something computers without touching 'em I have a WDS server, an image captured, and an answer file setup. I go to create a multicast transmission out of ...
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2answers
230 views

Unicast through Multicast

Suppose I have Multicast group with a group ID and I want to send packet to only one of the group members(as we are doing in anycasting). Is it possible? If yes then how?
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0answers
536 views

Multicast is not working with Linux

I have the multicast program which is working fine on windows , it is sending some message to range of IP. This works fine while I run it from windows, but when I run on Linux (with help of makefile) ...
2
votes
1answer
131 views

Multicast over 802.11b wireless

How do wireless routers behave with regards to multicast traffic? Given that nature of the shared physical medium routing to specific ports is not possible. Therefore, are mutlticast packets ...
3
votes
2answers
2k views

IGMP/Multicast routing in Linux

I need to route IGMP/Multicast traffic across two networks. I have a Linux box with two NICs, one public, one private. Need devices on the private network to flow to public. I'm pretty certain I ...
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1answer
323 views

Windows Deployment workflow

I've been digging around and getting WDS, WAIK, and the Deployment Workbench all configured and installed on a server we'll be using to roll images out to classrooms. I want to make sure I understand ...
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1answer
217 views

How to get UCARP to work over wireless?

I would like to get ucarp to work over a wireless (802.11g) interface, but the packages is never seen on the wired end. The setup looks like this: Box1 (10.0.0.11, wireless) -- AP -- (10.0.0.13, ...
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2answers
357 views

How to restore with multicast 3 systems: Windows 7, Windows 2008 and Linux?

We have used an old version of Norton Ghost to do backups and restores of computers. There are few groups of computers with the same hardware and we have used multicast. We have had Windows XP, ...
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2answers
626 views

Selecting interface for multicast traffic?

How do I specify an interface for multicast traffic? I need to connect to multicast group through vlan interface (tcpdump show traffic there) but I believe that IGMP request are sent throug eth0. ...