Broadcast not working between primary & secondary IP address

[stalin_cisco]

Hi Friends, I have recently configured secondary ip address on LAN Interface of Cisco C6509.. We have some application which needs to use broadcast traffic communication to communicate with client... Broadcast is working within subnet & also working from broadcast server to primary subnet. But not working from secondary subnet.. I have checked broadcast within secondary IP range & it's working fine... Secondary not working broadcast with primary and also with broadcast server... broadcast address is different for these subnet but both should be communicate since configured on same interface... When I went through Cisco website found that command "ip directed broadcast" which will help to pass broadcast to different subnet... But I'm not sure whether any other impact if I enable that command on particular Ethernet interface...

Please help me..

Urs,

Stalin P

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[Richard Burts]

Stalin P

I have read through your post several times but still do not have a clear understanding of the problem. Am I correct in assuming that you are talking about a single VLAN with a single VLAN interface, and on that one VLAN interface you have configured a primary IP address with its associated subnet, and have configured a secondary IP address with its associated subnet?

If that is the case then I would expect that any broadcast would be sent to all ports in the VLAN. Is this not the case?

Perhaps some additional details about what is working and what is not working would help me to understand the issue better.

HTH

Rick

[stalin_cisco]

Sorry for that... Thanks for the reply...

Yes, it's same vlan interface configured primary & secondary ip address...

Vlan interface : vlan555

Primary range : 10.5.0.0/24

Secondary range : 10.8.0.0/24

Broadcast server : 192.168.1.5

1) Broadcast msg working within primary segment

2) Broadcast msg working between broadcast server to primary subnet

3) Broadcast msg working within secondary subnet..

Problem:

-

---

4) Broadcast msg not working between secondary range to primary range

5) Broadcast msg not working between secondary range to broadcast server..

Not sure "ip directed broadcast" can solve this issue...

Thanks,

Stalin

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[stalin_cisco]

Hi Rick,

It's same vlan interface..

Issue: Broadcast not working from secondary subnet..

Vlan interface : vlan555

Primary range : 10.5.0.0/24

Secondary range : 10.8.0.0/24

Broadcast server : 192.168.1.5

1) Broadcast msg working within primary segment

2) Broadcast msg working between broadcast server to primary subnet

3) Broadcast msg working within secondary subnet..

Problem:

-

4) Broadcast msg not working between secondary range to primary range

5) Broadcast msg not working between secondary range to broadcast server..

Not sure "ip directed broadcast" can solve this issue...

Thanks,

Stalin

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[Richard Burts]

Stalin

Thanks for the additional information. It is fairly clear that there is a single VLAN and 2 subnets configured on that VLAN (which means that they are both in the same broadcast domain and from that I would believe that broadcast should work to both of them - and if I am  understanding your post broadcast is working to both of them). If that is not correct then please correct my understanding.

It is not clear to me whether the broadcast server at 192.168.1.5 is also in the same VLAN or whether it is somewhere else. Can you clarify this aspect of the environment?

Can you supply some additional detail about what is not working from the secondary subnet to the primary subnet  and also from the secondary subnet to the broadcast server?

HTH

Rick

[stalin_cisco]

Hi Rick,

192.168.1.5 is diffident vlan... It's our server vlan..

Let me explain clearly...

We have vlan555 for our office network, this vlan ip segment is well communicating broadcast message to broadcast server (192.168.1.5) located server vlan...

Our server team using TIBCO Rendevous for Broadcast messaging...

Now we have lacking of user IP address because it's 98% used... So we planed to configure secondary ip address..

After configured secondary IP address, new users on secondary IP segment can't communicate broadcast message to Broadcast server...

So I tested broadcast message within secondary range and it's working..

Then tested between primary subnet to secondary subnet and it's not working...

I suspect broadcast message is dropping somewhere...

When I went through Cisco.com, found the command "IP directed Broadcast"

I didn't configure this command because not sure whether any impact will happen or really useful to fix this issue...

Looking for advice to proceed..

Hope you understand my explanation about the setup...

Thanks,

Stalin P

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[Richard Burts]

Stalin

It is helpful to know that the broadcast server at 192.168.1.5 is in a different subnet. Since routers do not forward broadcast by default, and since you say it is working well to the primary subnet, then I would assume that something was done to allow broadcasts from the server to the primary subnet. If you determine what was done to get it to work with the primary then that would also need to be done for the secondary.

I do not know what has been done in your network. The typical solution for this kind of function is to configure ip helper-address on the router interface of the subnet where the broadcast server is and to configure ip directed-broadcast on the router interface where the clients are. Perhaps you can check and tell us if something was done on the router interface where the broadcast server is connected?

HTH

Rick