[CentOS] Simple routing question

Thu Sep 6 20:54:08 UTC 2012
James B. Byrne <byrnejb at harte-lyne.ca>

Well, I seem to be getting somewhere, although where exactly is open
to question.

I did this.  I put the virtual interface address 192.168.0.1 back onto
eth1 of the gateway host and restarted the network services.  The
ifcfg file looked like this:

BOOTPROTO=none
BROADCAST=192.168.255.255
DEVICE=eth1:192
IPADDR=192.168.0.1
IPV6INIT=no
MTU=""
NAME="LAN - Non-routable"
NETMASK=255.255.0.0
NETWORK=192.168.0.0
ONBOOT=yes
ONPARENT=yes

After the restart ip addr showed this:

3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP qlen 1000
    link/ether 00:25:90:60:11:8d brd ff:ff:ff:ff:ff:ff
    inet aaa.bbb.ccc.1/24 brd aaa.bbb.ccc.255 scope global eth1
    inet 192.168.0.1/24 brd 192.168.255.255 scope global eth1:192
    inet6 fe80::225:90ff:fe60:118d/64 scope link
       valid_lft forever preferred_lft forever

Note the cidr suffix on 192.168.0.1 = 24

That is not what I expected.  Restarting with the same config did not
change the initially observed outcome.

SO, I edited ifcfg-eth1:192 and added exactly one line:

PREFIX="16"

and restarted the network.  ip addr now shows this:

3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP qlen 1000
    link/ether 00:25:90:60:11:8d brd ff:ff:ff:ff:ff:ff
    inet aaa.bbb.ccc.1/24 brd aaa.bbb.ccc.255 scope global eth1
    inet 192.168.0.1/16 brd 192.168.255.255 scope global eth1:192
    inet6 fe80::225:90ff:fe60:118d/64 scope link
       valid_lft forever preferred_lft forever


Note that the cidr suffix is now 16.

Now, when I try and ping an address on the 192.168 netblock from host
C I see this:

# ping 192.168.209.43
PING 192.168.209.43 (192.168.209.43) 56(84) bytes of data.
>From 216.185.71.1: icmp_seq=2 Redirect Host(New nexthop: 192.168.209.43)
>From 216.185.71.1: icmp_seq=3 Redirect Host(New nexthop: 192.168.209.43)
>From 216.185.71.1: icmp_seq=4 Redirect Host(New nexthop: 192.168.209.43)
>From 216.185.71.1: icmp_seq=5 Redirect Host(New nexthop: 192.168.209.43)
>From 216.185.71.1: icmp_seq=6 Redirect Host(New nexthop: 192.168.209.43)


My question now is how do I get to 192.168.209.43?


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James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
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