Re: [CentOS] Basic Network question pinging different subnets

On Nov 17, 2007 1:25 AM, Bob Metelsky bobmetelsky@comcast.net wrote:

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,

Yes ! You have to learn how works IP networks :-) IP is wild and wide :-)

you can try this on your windows :

c:> route add 10.54.0.2 MASK 255.255.255.255 10.54.7.2

OR

do the same on your router at 10.54.7.1

OR (depend on how your linux box is configured)

c:> route add 10.54.0.0 MASK 255.255.255.0 10.54.7.16

But this should give you access on both 10.54.0.2 and 10.54.0.3

OR if routing is enable on 10.54.7.2

c:> route add 10.54.0.0 MASK 255.255.255.0 10.54.7.2

should also give you access to both 10.54.0.2 and 10.54.0.3

You just have to understand the first one other are just to spread out my IP knowledges. Ops, the last one is sometime useful to configure a device on another IP range, without reconfiguring your IP. Like when unpacking a new router with IP 192.168.123.1

Regards.

Thanks Bob

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