I have defined two different virtual IP on the same network card. I start an application that use the first virtual IP on port 1000 and everything works fine. When I run another application that use the second virtual IP on the same port number (1000), the listen function fails. If I change the port number even the second application works correctly. This is the right behavior or I do something wrong? I mean, I must use two different port or there is another workaround? thanks

make sure they're not also trying to listen on the local interface (127.0.0.1). You have to bind them to different addresses.

Also, can you provide ifconfig -a and application code snippets?

The conflict is on the virtual IP address not on the 127.0.0.1

I don't have the sources of the application.

This is the output of the ifconfig -a

ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:11:0A:30:16:64
inet addr:10.201.232.20 Bcast:10.201.232.63 Mask:255.255.255.192
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1413194 errors:0 dropped:0 overruns:0 frame:0
TX packets:1663285 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:268959925 (256.5 Mb) TX bytes:949122359 (905.1 Mb)
Interrupt:28

eth1 Link encap:Ethernet HWaddr 00:0A:5E:09:70:CB
inet addr:10.10.50.2 Bcast:10.10.50.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2356707 errors:0 dropped:0 overruns:0 frame:0
TX packets:1785641 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:185969013 (177.3 Mb) TX bytes:524518813 (500.2 Mb)
Interrupt:22

eth1:1 Link encap:Ethernet HWaddr 00:0A:5E:09:70:CB
inet addr:10.10.50.10 Bcast:10.255.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:522738 errors:0 dropped:0 overruns:0 frame:0
TX packets:545206 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:50757562 (48.4 Mb) TX bytes:60658728 (57.8 Mb)
Interrupt:22

eth1:2 Link encap:Ethernet HWaddr 00:0A:5E:09:70:CB
inet addr:10.10.50.11 Bcast:10.255.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:522738 errors:0 dropped:0 overruns:0 frame:0
TX packets:545206 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:50757562 (48.4 Mb) TX bytes:60658728 (57.8 Mb)
Interrupt:22

eth2 Link encap:Ethernet HWaddr 00:02:B3:3A:30:10
inet addr:9.10.50.2 Bcast:9.10.50.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:522738 errors:0 dropped:0 overruns:0 frame:0
TX packets:545206 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:50757562 (48.4 Mb) TX bytes:60658728 (57.8 Mb)
Interrupt:18 Base address:0x2040 Memory:f7df0000-f7df0038

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:4462347 errors:0 dropped:0 overruns:0 frame:0
TX packets:4462347 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1761852151 (1680.2 Mb) TX bytes:1761852151 (1680.2 Mb)