[CentOS] OT: Setting a CentOS to gateway a private IP address
Ross Walker
rswwalker at gmail.com
Tue Oct 21 19:20:38 UTC 2008
On Tue, Oct 21, 2008 at 3:02 PM, James B. Byrne <byrnejb at harte-lyne.ca> wrote:
> This is mildly off topic since it has more to do with TCP/IP networking
> than with CentOS per se. However, at the risk of ruffling a few feathers
> I would like some advice on how to resolve the following routing problem:
>
> Given:
> dual homed host running CentOS-5.2 with
> eth0 = 2xx.yyy.zzz.23
> eth1 = 192.168.219.1
>
> and a Cisco gateway at 2xx.1xx.y7y.1 with the following networks:
>
> interface FastEthernet0/1
> description connected to EthernetLAN
> ip address 10.0.0.1 255.0.0.0 secondary
> ip address 172.16.0.1 255.240.0.0 secondary
> ip address 192.168.71.1 255.255.255.0 secondary
> ip address 192.168.0.1 255.255.0.0 secondary
> ip address 2xx.yyy.zzz.1 255.255.255.0
> ip access-group 101 in
> ip inspect FastEthernet_0_1 in
> speed 100
> full-duplex
> !
> router rip
> version 2
> passive-interface FastEthernet0/0
> network 10.0.0.0
> network 172.16.0.0
> network 192.168.0.0
> network 2xx.yyy.zzz.0
> no auto-summary
Assuming that this Cisco box is for routing your Internet
traffic, I would NOT put any private network routing, or
any dynamic routing at all on it and use NAT on the
CentOS box.
> !
> ip classless
> ip route 0.0.0.0 0.0.0.0 FastEthernet0/0
>
> and with the following routes on the CentOS host:
>
> # route
> Kernel IP routing table
> Destination Gateway Genmask Flags Metric Ref Use Iface
> 192.168.219.0 * 255.255.255.0 U 0 0 0 eth1
> 2xx.yyy.zzz.0 * 255.255.255.0 U 0 0 0 eth0
> 169.254.0.0 * 255.255.0.0 U 0 0 0 eth1
> default gw-fibrewire 0.0.0.0 UG 0 0 0 eth0
> # ip route
> 192.168.219.0/24 dev eth1 proto kernel scope link src 192.168.219.1
> 2xx.yyy.zzz.0/24 dev eth0 proto kernel scope link src 2xx.yyy.zzz.23
> 169.254.0.0/16 dev eth1 scope link
> default via 2xx.yyy.zzz.1 dev eth0
>
>
> The situation is this.
>
> >From the host itself I can ping 192.168.218.102 on 192.168.219.0/24
Was that a typo 192.168.218.102?
> >From any other host on 2xx.1xx.y7y.0/24 I can ping 192.168.219.1
Yes, cause it a local interface on router 2xx.yyy.zzz.23, discoverable
by ICMP.
> >From any other host on 2xx.1xx.y7y.0/24 I cannot ping 192.168.219.102
You need to have a route in the Cisco's table for 192.168.219.0/24 or you
need to get RIP working between 2xx.yyy.zzz.23 and 2xx.yyy.zzz.1
> What setup steps on the CentOS host have I overlooked or what
> configuration errors have I committed?
Probably getting routed/gated running, setting active/passive interfaces,
broadcast or multicast RIP, host routes/default routes, etc.
> As I am a digest subscriber please use "reply all" so that I get an
> immediate copy of any replies.
List always strips off the members email :-(
-Ross
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