Can you turn off your windows firewall to do a test? It seems like I've had
problems with multicast working in the past with windows firewalls, but it may
have just been a server running on windows with a client somewhere else not
being able to get to the service port until I allow application access (you know
the popup that usually occurs when you install a new version of Java on windows
and run a network application for the first time). I've used a lot of unicast
to solve those issues, but there are times when multicast is the only real
solution for lookup.
Gregg Wonderly
On 10/5/2011 3:58 AM, Sergio Aguilera Cazorla wrote:
Hello,
No, we are not using VLAN, all the computers in the office belong to the
same LAN.
Regards.
2011/10/5 richard nicholson<[email protected]>
Sergio
As you using layer II VLAN's between your physical switches? If so - make
sure your network
folks have IGMP turned on - on the switch interlinks.
Cheers
Richard
On 5 Oct 2011, at 09:38, Sergio Aguilera Cazorla wrote:
Hello,
Our network administrators say that *our company's switches do not block
multicast or broadcast traffic*. To check if this it's true, we've
forgotten
about Reggie and we've written a little Java program that simply uses a
MulticastSocket to send packets to the multicast IP *224.0.1.84 and
attacking the port 4160*. Of course, this program failed in the network
office, while it worked perfectly on my home's network.
We are completely sure that it's a problem related to multicast packets.
Maybe it's related to Windows XP or 7 Firewall? In the company there is a
Group Policy commanding the Firewall, but we can define some exceptions
and
we have the multicast/broadcast response enabled. Is that enough, or is
there some other issue that remains hidden?
Please, any hint is welcome, because our goal is to deploy this software
in
a production environment, not only in a domestic network!
Thanks and regards
2011/9/29 Christopher Dolan<[email protected]>
Yes, most enterprise switches block multicast by default. That's
probably
your issue.
Another possible issue is reverse DNS. If reggie is broadcasting a
private
hostname or IP address for other machines to call back to it, then it's
not
going to work. We've also had issues with dual-NIC servers where clients
always try to connect to the primary NIC (as specified in the Windows
interface binding order) and do not fail over to the secondary NIC. The
usual cause of that problem is passing a null host to
TcpServerEndpoint.getInstance() because in that code path, JERI just
picks
the first IP address from a reverse DNS lookup. The solution in that
case is
to instead pass the results of
InetAddress.getLocalHost().getCanonicalHostName() as the hostname, or
hard-code the public host name.
I'm suspicious of your "just once" result. Maybe you changed the group
name? Remember that the group is case-sensitive.
Chris
-----Original Message-----
From: Sergio Aguilera Cazorla [mailto:[email protected]]
Sent: Thursday, September 29, 2011 1:16 PM
To: [email protected]
Subject: Re: Reggie's visibility in discovery process
Hello,
At last we could perform some testing on Reggie's discovery using
multicast
protocol. I can provide the following results:
- The program performs perfectly when we make a Unicast discovery,
attacking
directly the URL where the Lookup service is located.
- We can ping the two machines. Even, we can acces the folder server by
the
HTTP server, and get the reggie-dl.jar classfiles needed to communicate
with
the Lookup.
- All machines in the office are Windows XP SP3 and Windows 7. None of
the
combinations server/client XP-7 has thrown a good result.
- We are communicating through switches in the LAN of a enterprise. Do
you
think that multicast packets are bein blocked by intermediate nodes?
- The most misteryous fact: we could perform multicast discovery
succesfully
*just once*, the first time we tried. That's suspicious, is there some
class
or service that remains hidden and doesn't allow you to perform
multicast
discovery more than once?
Any help on reggie's weird behaviour is very welcome. If I can solve
this
problem, no doubt I will write a short explanation for the community,
because I think it has to be a very common problem.
Regards.
2011/9/22 Иван Бишевац<[email protected]>
1. Could you ping two machines?
2. Which operating system you use?
3. Are you communicating through router?
--
*Sergio Aguilera*
