Forwarding of multicast packets between two subnets with two NICS - Does not work

Similar Threads:

1.how to forward packets on two NICs

Hi all

I have to build a sniffer on our voip network so as to monitor what is going 
wrong on it (bad communications quality) and my problem is that I can't 
mirror the traffic because the switchs are not manageable. All the IP phones 
are on the same subnet and the IPBX is the gateway.
Because I am not familiar with Voip protocols, I don't know really how all 
this stuff is working... And I am looking for a solution which won't need to 
change the IP topology... if it's possible.


I had the idea to configure the sniffer with two NIC and to forward all the 
packets from one NIC to the other one, like a switch with 2 ports if you 
want (I know that this is not a very good way to act but has I have said, I 
would like to avoid changing the IP of the IPBX).

Do you think it is a solution ? If yes, do you know how to configure that ? 
if no, do you see another solution ?

I have found a package call parprouted which allows to forward the ARP 
requests, now I guess that I just have to find the same thing for IP packets 
as there is no dhcp/bootp protocols here...


thanks in advance

2.Forwarding multicast packets in Linux, for different subnets.

Here is my setup:


                               Linux Box with two NICS
PC1         router          NIC(eth0)---NIC(eth1)          router
 PC2
192.168.1.100 192.168.1.1 192.168.1.111 192.168.4.114 192.168.4.1
192.168.4.100


Linux Box:
---------
/proc/sys/net/ipv4/ip_forward


PC1
----
ping 192.168.4.1 - works
ping 224.0.0.1 - only get reply from 192.168.1.1 and 192.168.1.111


PC2
----
ping 192.168.4.1 - works
ping 224.0.0.1 - only get reply from 192.168.4.1 and 192.168.1.114


The Linux box does not seem to forward multicast packets. Can someone
shed any light on this?

Thanks,

3.two dsl connections, two routers, dual nics on linux box , want to run two websites

Hello,

I have two dsl connections, with one public ip on each. I have a linux
box with two nic cards.

xx.xx.xx.xx(WAN)---ROUTER(LAN23.123.45.110) ---- MYLINUX
(23.123.45.107) eth1
yy.yy.yy.yy(WAN)---ROUTER(LAN192.182.1.1)   ---- MYLINUX
(192.168.1.100) eth0

I have apache listening on both interfaces. 

Problem:

1. How do I make the packets route back to the gateway from which they
originate.

Currently the gateway marked as "default" is able to serve content
from the apache. The other one cannot.

I tried adding static routes, but that didn't work.

Any help is appreciated.

Thanks
Jay

---------------------------------------------------------------------
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref   
Use Iface
adsl-23-123-45- adsl-23-123-45- 255.255.255.255 UGH   0      0       
0 eth1
23.123.45.0     *               255.255.255.0   U     0      0       
0 eth1
192.168.1.0     *               255.255.255.0   U     0      0       
0 eth0
loopback        *               255.0.0.0       U     0      0       
0 lo
default         192.168.1.1     0.0.0.0         UG    1      0       
0 eth0


eth0      Link encap:Ethernet  HWaddr 00:0D:87:57:A0:DE
          inet addr:192.168.1.100  Bcast:192.168.1.255 
Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3060612 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3577217 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:1566982235 (1494.3 Mb)  TX bytes:1126616733 (1074.4
Mb)
          Interrupt:11 Base address:0xe000

eth1      Link encap:Ethernet  HWaddr 00:40:05:39:0E:EA
          inet addr:23.123.45.107  Bcast:68.123.24.255 
Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:90635 errors:0 dropped:0 overruns:0 frame:0
          TX packets:31082 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:23017102 (21.9 Mb)  TX bytes:13283751 (12.6 Mb)
          Interrupt:11 Base address:0xe000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:11888 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11888 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:6920794 (6.6 Mb)  TX bytes:6920794 (6.6 Mb)

4.DHCP With Two NICs and Two Subnets

As long as the second NIC is actually connected to and has an IP address on
the subnet it will respond to discover broadcasts by providing an IP from
the scope for that subnet.  If however, a request is received from a relay
agent, the server will respond with an IP from the scope which matches the
IP of the interface on which the discover request was received.

Doug Sherman
MCSE, MCSA, MCP+I, MVP

< XXXX@XXXXX.COM > wrote in message
news: XXXX@XXXXX.COM ...
> I have a Win2k3 AD network.
>
> Two Vlans/subnets.
>
> A DHCP server with one NIC serving out both subnets. I want to install
> a second NIC on the second subnet to only serve out DHCP address to
> that subnet. So one NIC for one subnet. I'm fairly certain that this is
> possible. Do I need to configure the DHCP server any different?
>

5.SOS - two NICs installed on a PC do not work at the same time

This is a very strange issue.  We install two NICs on a PC (Linux or
Windows), and use two crossover Ethernet cables to connect each NIC to a
different Ethernet port on an iSCSI router.

NIC 1 (IP 192.168.100.200) connects to port 1 (IP 192.168.100.121) of iSCSI
router.
NIC 2 (IP 192.168.100.201) connects to port 2 (IP 192.168.100.123) of iSCSI
router.

From the PC, we can ping 192.168.100.123, but not 192.168.100.121.  If we
disconnect the cable to 192.168.100.123, then we can ping 192.168.100.121.
Both NIC use the same configuration but different IPs.

I would appreciate it if some one can give me a hint why we can not ping
192.168.100.121.

Thanks,


T.

6. One DHCP server - two interfaces - two subnets

7. Two NICs, Two networks, secure websites

8. we have two different subnets, machines talking on oneway only, not both ways