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jzoudavy 09-15-2014 07:20 PM

SLES network config question
 
1 Attachment(s)
Hi experts

I am confused by something: this VM 4v7: It has the following:
Code:

4v7:~ # ifconfig
eth3      Link encap:Ethernet  HWaddr 00:50:56:11:36:46
          inet addr:10.131.226.110  Bcast:10.131.226.255  Mask:255.255.255.0

eth10    Link encap:Ethernet  HWaddr 00:50:56:00:36:46
          inet addr:10.131.224.110  Bcast:10.131.224.255  Mask:255.255.255.0
 
 

4v7:~ # route
Kernel IP routing table
Destination    Gateway        Genmask        Flags Metric Ref    Use Iface
10.131.224.0    10.131.224.1    255.255.255.0  UG    0      0        0 eth10
10.131.226.0    *              255.255.255.0  U    0      0        0 eth3
10.130.102.0    *              255.255.255.0  U    0      0        0 eth11
link-local      *              255.255.0.0    U    0      0        0 eth10
loopback        *              255.0.0.0      U    0      0        0 lo
default        10.130.102.1    0.0.0.0        UG    0      0        0 eth11

yast2 config is attached.

What I am confused about is why is the GW from route for 10.131.226.0 a * instead of 10.131.226.1?

Right now this VM is problematic because it can reach some IPs on the same subnet but not others. so 10.131.224.100 is reachable but .101 is not. and they are all on the same physical switch as well.

I know from basic routing that the weirdness from 226 shouldn't affect 224, but I have plenty of working examples with similar setups and this is the only thing out of place.

any help on this is greatly appreciated.


Thanks

EDIT: no firewall either. This VM was cloned from a working VM, I just cloned it and modified the IPs.

EDIT 2: I might have an IP conflict it seems... will double check

smallpond 09-16-2014 01:26 PM

If you aren't on the same subnet as another IP, then you have to send packets through a gateway to reach it. If you are on the same subnet and don't need to send through a gateway, then the routing table should have '*' for no gateway required.

jzoudavy 09-16-2014 02:06 PM

hmmm, true. but here is where it doesn't make sense:

1. I have the same setup (in the attached screenshot) via yast but some show gateway for 226.1 and this one shows a *

2. I have 3 networks. network A is my default, it's my default gw. Network B and C are 226.x and 224.x, so therefore both should have a gateway in the routing table. But it doesn't for 226.x.

thanks

kaito.7 09-23-2014 07:37 AM

Hi jzoudavy,

As you can see from the output of the "route" command, "G" is the flag that signifies that the route is to a gateway. If this flag is not present then we can say that the route is to a directly connected destination.
So check the routes that you had added (/etc/sysconfig/network/routes).

The second one that I chcecked is at ifconfig
eth3 HWaddr 00:50:56:11:36:46

eth10 HWaddr 00:50:56:00:36:46

and at the attached file the device is the same for the both networks. Maybe there is a conflict (This VM was cloned from a working VM, I just cloned it and modified the IPs). You have to change and the MAC addresses.

BRs,

Spyros


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