Host not reachable problem

Host not reachable problem

[Steffen Heil]

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Hi

I have a server, which has 68 IPs. 4 for it's own network interfaces and a
network of 64 addresses for xen domains and vpn.
Now, only some of these domains are live and only some VPN clients online.
As such, only some IPs will be available, ohters will not.

For every available IP there is an entry in the routing table like this:
<singleIP> 0.0.0.0         255.255.255.255 UH    0      0        0
<virtualinterface>

Moreover there is a default route:
0.0.0.0         <ispgateway>   0.0.0.0         UG    0      0        0 eth0

ip_forward contains 1

Now, packets for IPs that are offline right now, are routed to the main ip
of my server, which is suppost to forward them.
This works for systems that are online.

However, packets for hosts wich are not online are routed by via the default
route.
What I would need is a routing table entry which routes my /26-network to
"host not reachable" and which has a lower priority than my explizit routing
rules.
How can I do that?

Regards,
  Steffen


BTW: Where can I set ip_forward for the next reboot?

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Re: Host not reachable problem

[Andre Grueneberg]

Steffen Heil wrote:
> What I would need is a routing table entry which routes my /26-network to
> "host not reachable" and which has a lower priority than my explizit routing
> rules.
> How can I do that?

ip route add unreachable <network>/26

Your host routes are more specific so they overrule this network rule.

Andre
-- 
RECOVER.COM: a little slice of hell.

RE: Host not reachable problem

[Steffen Heil]

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Hi

> ip route add unreachable <network>/26

I didn't realize there was a "unreachable" target...
Thanks a lot.

BTW: Is there a way to make this and ip_forward permanent (for reboots)?

Regrads,
  Steffen

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Re: Host not reachable problem

[Gáspár Lajos]

>
> Hi
>
>   
>> ip route add unreachable <network>/26
>>     
>
> I didn't realize there was a "unreachable" target...
> Thanks a lot.
>
> BTW: Is there a way to make this and ip_forward permanent (for reboots)?
>
>   
With a startup script -> YES !
> Regrads,
>   Steffen
>   

Re: Host not reachable problem

[Gáspár Lajos]

>
> Hi
>
>   
>> ip route add unreachable <network>/26
>>     
>
> I didn't realize there was a "unreachable" target...
> Thanks a lot.
>
> BTW: Is there a way to make this and ip_forward permanent (for reboots)?
>
>   
With a startup script -> YES !
> Regrads,
>   Steffen
>