remapping ip addresses: how?

Hi,

sorry if the question is silly for thus ng, but I have already
tried to answer for the whole day without results.

I need a way to remap an IP address to another, in such a way that
all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.

In particular, 1.2.3.4 is an external ip while 10.20.30.40 is my
local ip.

In other words, I need a way to specify that the traffic directed
to a certain external ip will instead be routed to my local ip.

I have Fedora Core 5.

Thanks in advance for any help.

Alessandro

On 2006-09-06, Alessandro Russo <(E-Mail Removed)> wrote:
> I need a way to remap an IP address to another, in such a way that
> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.

Yes, that's commonly called 'NAT' or Network Address Translations,
see the IPTable documentation for DNAT (Destination NAT)

Davide

--
"I'm not lean and mean, I'm surly and anorexic".
-- Chris "Saundo" Saunderson on alt.sysadmin.recovery

Davide Bianchi wrote:
> On 2006-09-06, Alessandro Russo <(E-Mail Removed)> wrote:
>> I need a way to remap an IP address to another, in such a way that
>> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.
>
> Yes, that's commonly called 'NAT' or Network Address Translations,
> see the IPTable documentation for DNAT (Destination NAT)
>

I have tried, but I don't understand what I have to do.
I tried what I found at

http://openskills.info/topic.php?ID=125

but no way.

Any hints? Thanks again.

Ale

In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
> Davide Bianchi wrote:
>> On 2006-09-06, Alessandro Russo <(E-Mail Removed)> wrote:
>>> I need a way to remap an IP address to another, in such a way that
>>> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.

>> Yes, that's commonly called 'NAT' or Network Address Translations,
>> see the IPTable documentation for DNAT (Destination NAT)

> I have tried, but I don't understand what I have to do.
> I tried what I found at


The "Linux Home Server HOWTO" looks exactly like what you want
and was updated to suit FC 5:

http://www.brennan.id.au/

As already mentioned "Destination NAT" is what you want, not that
I have ever used this document but it seems from a short look
well written.

I'd urge you to check the chapter about yum, you can ease up
installing/updating software pretty much if using 'yum'!

Good luck

[..]

--
Michael Heiming (X-PGP-Sig > GPG-Key ID: EDD27B94)
mail: echo (E-Mail Removed) | perl -pe 'y/a-z/n-za-m/'
#bofh excuse 455: This code passes Torvalds test grades 0,
1 and 2 (looks ok, compiles and boots).

Michael Heiming wrote:
> In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
>> Davide Bianchi wrote:
>>> On 2006-09-06, Alessandro Russo <(E-Mail Removed)> wrote:
>>>> I need a way to remap an IP address to another, in such a way that
>>>> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.
>
>>> Yes, that's commonly called 'NAT' or Network Address Translations,
>>> see the IPTable documentation for DNAT (Destination NAT)
>
>> I have tried, but I don't understand what I have to do.
>> I tried what I found at
>
>
> The "Linux Home Server HOWTO" looks exactly like what you want
> and was updated to suit FC 5:
>
> http://www.brennan.id.au/
>
> As already mentioned "Destination NAT" is what you want, not that
> I have ever used this document but it seems from a short look
> well written.
>
> I'd urge you to check the chapter about yum, you can ease up
> installing/updating software pretty much if using 'yum'!
>

I tried

iptables -t nat -A PREROUTING -d 1.2.3.4 -j DNAT --to-destination 10.20.30.40

with no effects.

As far I understood, this should redirect to 10.20.30.40 everything that
was originally directed to 1.2.3.4. Or I'm wrong?

Ale

In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
> Michael Heiming wrote:
>> In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
>>> Davide Bianchi wrote:
>>>> On 2006-09-06, Alessandro Russo <(E-Mail Removed)> wrote:
>>>>> I need a way to remap an IP address to another, in such a way that
>>>>> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.

>>>> Yes, that's commonly called 'NAT' or Network Address Translations,
>>>> see the IPTable documentation for DNAT (Destination NAT)

>>> I have tried, but I don't understand what I have to do.
>>> I tried what I found at


>> The "Linux Home Server HOWTO" looks exactly like what you want
>> and was updated to suit FC 5:

>> http://www.brennan.id.au/

> I tried

> iptables -t nat -A PREROUTING -d 1.2.3.4 -j DNAT --to-destination 10.20.30.40

> with no effects.

> As far I understood, this should redirect to 10.20.30.40 everything that
> was originally directed to 1.2.3.4. Or I'm wrong?

There is more then a single command needed and I can't look into
your box. Did you worked through the documentation I pointed out
to you?

You can see your nat setup with '/sbin/iptables -t nat -nvL',
again all this is in the howto, you just need to work trough it.

Good luck

--
Michael Heiming (X-PGP-Sig > GPG-Key ID: EDD27B94)
mail: echo (E-Mail Removed) | perl -pe 'y/a-z/n-za-m/'
#bofh excuse 435: Internet shut down due to maintenance

Michael Heiming wrote:
> In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
>> Michael Heiming wrote:
>>> In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
>>>> Davide Bianchi wrote:
>>>>> On 2006-09-06, Alessandro Russo <(E-Mail Removed)> wrote:
>>>>>> I need a way to remap an IP address to another, in such a way that
>>>>>> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.
>
>>>>> Yes, that's commonly called 'NAT' or Network Address Translations,
>>>>> see the IPTable documentation for DNAT (Destination NAT)
>
>>>> I have tried, but I don't understand what I have to do.
>>>> I tried what I found at
>
>
>>> The "Linux Home Server HOWTO" looks exactly like what you want
>>> and was updated to suit FC 5:
>
>>> http://www.brennan.id.au/
>
>> I tried
>
>> iptables -t nat -A PREROUTING -d 1.2.3.4 -j DNAT --to-destination 10.20.30.40
>
>> with no effects.
>
>> As far I understood, this should redirect to 10.20.30.40 everything that
>> was originally directed to 1.2.3.4. Or I'm wrong?
>
> There is more then a single command needed and I can't look into
> your box. Did you worked through the documentation I pointed out
> to you?
>
> You can see your nat setup with '/sbin/iptables -t nat -nvL',
> again all this is in the howto, you just need to work trough it.
>

sbin/iptables -t nat -nvL says:

Chain PREROUTING (policy ACCEPT 1607 packets, 84568 bytes)
pkts bytes target prot opt in out source destination
0 0 DNAT all -- * * 0.0.0.0/0 149.132.103.59

to:1.60.153.33

where "to:1.60.153.33" is on the right of 149.132.103.59.

It seems ok to me, but it should be wrong.

Ale

In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
> Michael Heiming wrote:
>> In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
>>> Michael Heiming wrote:
>>>> In comp.os.linux.networking Alessandro Russo <(E-Mail Removed)>:
>>>>> Davide Bianchi wrote:
>>>>>> On 2006-09-06, Alessandro Russo <(E-Mail Removed)> wrote:
>>>>>>> I need a way to remap an IP address to another, in such a way that
>>>>>>> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.

>>>>>> Yes, that's commonly called 'NAT' or Network Address Translations,
>>>>>> see the IPTable documentation for DNAT (Destination NAT)

>>>>> I have tried, but I don't understand what I have to do.
>>>>> I tried what I found at

>>>> The "Linux Home Server HOWTO" looks exactly like what you want
>>>> and was updated to suit FC 5:

>>>> http://www.brennan.id.au/
[..]

> sbin/iptables -t nat -nvL says:

> Chain PREROUTING (policy ACCEPT 1607 packets, 84568 bytes)
> pkts bytes target prot opt in out source destination
> 0 0 DNAT all -- * * 0.0.0.0/0 149.132.103.59

> to:1.60.153.33

> where "to:1.60.153.33" is on the right of 149.132.103.59.

> It seems ok to me, but it should be wrong.

It seems wrong to me. Please start reading and using the "Linux
Home Server HOWTO" now!

http://www.brennan.id.au/

--
Michael Heiming (X-PGP-Sig > GPG-Key ID: EDD27B94)
mail: echo (E-Mail Removed) | perl -pe 'y/a-z/n-za-m/'
#bofh excuse 465: Fatal Error: Found [MS-Windows] System ->
Repartitioning disk for Linux...

Hello,

Alessandro Russo a écrit :
>
> I need a way to remap an IP address to another, in such a way that
> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.
>
> In particular, 1.2.3.4 is an external ip while 10.20.30.40 is my
> local ip.
>
> In other words, I need a way to specify that the traffic directed
> to a certain external ip will instead be routed to my local ip.

Try :

iptables -t nat -A OUTPUT -d 1.2.3.4 -j DNAT --to 10.20.30.40

The OUTPUT chain sees locally generated packets whereas PREROUTING sees
incoming packets.

Pascal Hambourg wrote:
> Hello,
>
> Alessandro Russo a écrit :
>>
>> I need a way to remap an IP address to another, in such a way that
>> all the traffic directed to, say, 1.2.3.4, will go to 10.20.30.40.
>>
>> In particular, 1.2.3.4 is an external ip while 10.20.30.40 is my
>> local ip.
>>
>> In other words, I need a way to specify that the traffic directed
>> to a certain external ip will instead be routed to my local ip.
>
> Try :
>
> iptables -t nat -A OUTPUT -d 1.2.3.4 -j DNAT --to 10.20.30.40
>
> The OUTPUT chain sees locally generated packets whereas PREROUTING sees
> incoming packets.

Thanks a lot, it worked.

Ale