[CentOS] Re: Basic Network question pinging different subnets

[Scott Silva]

on 11/16/2007 4:25 PM Bob Metelsky spake the following:
> Hi Im a little perplexed by this situation
> 
> I have centos 4.5 installed on 2 pcs - each with 2 network cards
> 
> machine 1
> 
> eth0      Link encap:Ethernet  HWaddr 00:14:2A:6B:C8:CC
>          inet addr:10.54.7.2  Bcast:10.54.7.255  Mask:255.255.255.0
>         eth1      Link encap:Ethernet  HWaddr 00:11:50:9B:A2:90
>          inet addr:10.54.0.2  Bcast:10.54.0.255  Mask:255.255.255.0
> 
> machine 2
> 
> eth0      Link encap:Ethernet  HWaddr 00:14:2A:69:4C:47
>          inet addr:10.54.7.3  Bcast:10.54.7.255  Mask:255.255.255.0
> 
> eth1      Link encap:Ethernet  HWaddr 00:11:50:9B:A5:0A
>          inet addr:10.54.0.3  Bcast:10.54.0.255  Mask:255.255.255.0
> 
> 
> machine 1 & 2 can ping each other  on either subnets
> 
> machine 3 (windows)...
> 
> C:\>ipconfig
> 
>        Connection-specific DNS Suffix  . :
>        IP Address. . . . . . . . . . . . : 10.54.7.16
>        Subnet Mask . . . . . . . . . . . : 255.255.255.0
>        Default Gateway . . . . . . . . . : 10.54.7.1
> 
> cant ping anything on the 10.54.0 subnet, nor does that subnet show up 
> ip using a port scanner...
> 
> C:\>ping 10.54.0.2
> 
> Pinging 10.54.0.2 with 32 bytes of data:
> Request timed out.
> Request timed out.
> 
> C:\>ping 10.54.7.2
> 
> Pinging 10.54.7.2 with 32 bytes of data:
> Reply from 10.54.7.2: bytes=32 time<1ms TTL=64
> Reply from 10.54.7.2: bytes=32 time<1ms TTL=64
> 
> 
> Any ideas why this is happening? I dont have a firewall on the 10.54 
> address,
> 
Machine 3 is locked to its subnet by the subnet mask. Your above mask of 
255.255.255.0 only lets the windows machine talk to 10.54.7.1 through 
10.54.7.254. Without adding a route to that other address, or a virtual IP 
address in that address space, the windows machine can't see or communicate on 
the other subnet.


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