topic Re: ping + multicast in Operating System - Linux

ping + multicast

Asaf_11 — Thu, 12 Jan 2006 02:27:09 GMT

I'm using Multicast Address with 2 linux servers on the same segment (for jboss Cluster)
The Cluster is able to find all is members(I assume this is because he is using the multicast address) when i'm using netstat -g on both servers i can see that eth0 got 228.1.2.3 multicast address.
my question is why when i'm using ping from one server the only response is from this server and not from the other server, maybe ping doesnt work so good with multicast and if so hoe can i check my multicast address

thanx.

Re: ping + multicast

Vitaly Karasik_1 — Thu, 12 Jan 2006 06:50:46 GMT

This is strange... Ping should work with multicast.
How many NICs do you have on each host?
Can you send us "ifconfig" output from both hosts?

Re: ping + multicast

Asaf_11 — Thu, 12 Jan 2006 08:26:40 GMT

I have only one nic in each server
when Im typing netstat -g
i got

eth0 230.1.2.3
eth0 228.1.2.3
eth0 230.0.0.4

from all of those only 230.0.0.4 is working
when i ping it i'm getting two answers from both servers.

all the other multicast address only return one answer from the localhost when ping to

anyone got idea?

Re: ping + multicast

Vitaly Karasik_1 — Thu, 12 Jan 2006 09:23:04 GMT

1) >when Im typing netstat -g
>i got
>eth0 230.1.2.3
>eth0 228.1.2.3
>eth0 230.0.0.4

do you receive the same answer on all servers?

2) may be your router/switch allow only one m/cast address for now?

Re: ping + multicast

Asaf_11 — Thu, 12 Jan 2006 09:38:05 GMT

i'm using local subnet(not using a router)

i saw that some address work and some not

i defined this address to both servers:
230.1.2.3
228.1.2.3
230.0.0.4
224.0.0.40

what happend is that the first 2 didnt work, i got answer only from the localhost
the last 2 work and i got answer from both servers
when i ping from a third server on the subnet i got the same resault:
the first 2 address didnt answer at all
the last 3 returnd 2 resault from the defined server.

very strange