NAT configuration...

[powell molleti]

Hi,
 
 Yes you can ping 10.0.0.1 from 10.0.0.0/24 network
 because of the following lines in the mazu file which
 determine the flow of the ICMP echo request packet.

 Look at lines 195 - 197
 intern_arp_class[2] -> Strip(14)
  	-> CheckIPHeader
	-> ip_from_intern;

 now when you look at ip_from_intern(lines 184 - 187)
 ip_from_intern :: IPClassifier(dst host intern,
			dst net intern,
			dst tcp port ftp,
			-);
 
 Your ping packet will output at ip_from_intern[0].

 as you can see at the line 198:
 ip_from_intern[0] -> my_ip_from_intern; // stuff for 
                               //  10.0.0.1 from
inside

 you are sending the packet to another classifier
 my_ip_from_intern (lines 188 - 193) and the ICMP
 packet which is neither TCP or UDP will be 
 outputed as my_ip_from_intern[5] , and look at line 
 206 

 206: my_ip_from_intern[5] -> ip_to_linux; // non TCP 
                             // or UDP traffic, to
linux
 hence linux will reply your ICMP echo request.

 Now you have tried to ping the external interface  
 (172.25.79.156).

 Look at the fate of this ICMP packet.
 try to sketch the path as described above and you
will 
 see that the  packet will be  classified at
 ip_from_intern(lines 184 - 187) and will be emitted
at
 ip_from_intern[3] right , now look at line 211(end) 

 211 : ip_from_intern[3] -> [0]rw;	// stuff for 
                                        // outside

 The packet is goin for rw , check rw now at line 112.

 Your packet headers will be rewritten by rw replacing
 the packet's src ip with the external and leaving the
 packet's dest ip as it is. Next look at line 146 
 
 146: rw[0] -> ip_to_extern_class :: IPClassifier(dst 
                                    host intern, -);

 as you can see your packet with dst ip  as extern
will
 be emitted as ip_to_extern_class[1] , as you can
 obviously see at line 148 
 
 148: ip_to_extern_class[1] -> ip_to_extern; 
 your packet is sent to the next hop and so it gets
 discarded.

 Hence you dont get a ping reply for your request to
 the external interface from the interal network.

 Are you able to reach the web. Try check a website or
 something and if you are not able to reach then there
 is a problem is with your network topology.
 As you have shown in your diagram is the machine
 (the extern_next_hop) connected to the same switch as
 the external interface of the click box?.
 
 I hope this helps. If any mistakes in the way i
 understood or explained the problem please correct me
 cause i am a newbie too. 

 cya
 powell



--- Juan Luis Baptiste <juancho at metallica.com> wrote:
> Hi,
> 
> I'm trying tu use the mazu-nat.click configuration
> file, but I haven't been
> able to get it to
> work.
> My network setup is like this:
> 
>                    10.0.0.2/8
>                          |
>                          |
>                   10.0.0.1/8 (eth1
> 00:60:97:C0:D4:74)
>                   172.25.79.156/16 (eth0
> 00:50:8B:65:2C:23)
>                          |
>                          |
>         --------------------------
>         | 172.25.* network |
>         --------------------------
>                          |
>                          |
>                 172.25.0.1/16 (08:00:20:AC:09:45)
>                          |
>                          |
>                  INTERNET
> 
> The configuration I'm using with mazu-nat is the
> following:
> 
> AddressInfo(
>   intern 	10.0.0.1	10.0.0.0/8	00:60:97:C0:D4:74,
>   extern	172.25.79.156	172.25.79.0/24
> 00:50:8B:65:2C:23,
>   extern_next_hop				08:00:20:AC:09:45,   
>   intern_server	10.0.0.10
> );
> 
> The rest of the file is unmodified. When I load the
> configuration file into the
> kernel module, I can only ping
> 10.0.0.1
> from 10.0.0.2, I can't even see the other interface
> of the NAT (172.25.79.156)
> or beyond from there, but if the
> module
> isn't loaded, I can see the other interface but not
> beyond from there.
> 
> Any ideas?
> 
> Juan Luis Baptiste M.
> email: juancho at metallica.com
> 
>
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