[nos-bbs] HTTP server restriction maybe

[(Skip) K8RRA]

I hate to do this Jay, but the formula does not work here...

On Tue, 2007-04-17 at 15:03 -0400, Jay Nugent wrote:

> Greetings Skip (et al),
> 
> On Tue, 17 Apr 2007, (Skip) K8RRA wrote:
> 
> > On Tue, 2007-04-17 at 12:08 -0500, Barry Siegfried wrote:



> 
>    Nada.  No way.  Uh uh. No sirie!  NAT, cough gag hurl!
> 
>    The "source" address of an outgoing packet is determined by the
> *interface* address used.  And which *interface* is determined by the
> destination address you are trying to reach, and what *interface* the
> *route table* says you must use to get to the desired destination.

The above protocol did not work here - the FROM IP remained 192... as
seen in the tun0 trace.
I used ping 44.102.132.20 (me) and 44.102.132.1 (Dave)
In all cases the ICMP packet from ping did go out the radio as it should
- OUTBOUND is OK... except for FROM IP.
The route table is attached for your inspection.

> 
>    That's alot to chew on.  Let me explain...
> 
>    I have a Linux box here.  It's address is 216.144.208.6.

I have a Linux box here with FC-6 and jnos on it.  The host is static
192.168.1.32

>   However, I 
> would like this box to also be able to reach the HTTP webpages at 
> wb8rcr.ampr.org.  To do this I added an additional *interface* to this box 
> along with the supporting *route* entry, as follows:
> 
>    ifconfig eth0:44 44.102.1.239
> 
>    route add -net 44.0.0.0/8 gw 44.102.1.1

My choices were both:

    ifconfig eth0:44 44.102.132.229
    route add -net 44.102.0.0/16  tun0

and:

   ifconfig tun0:44 44.102.132.229
   route add -net 44.102.0.0/16 tun0

In both cases the ifconfig showed the desired added interface - I don't
have yours for comparison but they look OK to me.

Interesting fact (FYI):
In the first case "eth0:44" the ifconfig statement added a route to the
host table "44.0.0.0 * ... eth0"
In the second case "tun0:44" there was no route added to the table
automatically.

> 
> 
>    So at this point I now have a Linux box that will send ALL it's traffic
> out onto my ethernet as 216.144.208.6 *UNLESS* it happens to be going to
> anything in the AMPRnet (44/8).  In which case it flows out onto my
> ethernet addressesd FROM 44.102.1.239 and GATEWAYED through 44.102.1.1
> (which happens to be my JNOS/Hamgate on that very same ethernet).
> 
>    Now, remember what I said about "Think like a Packet" the other day.  
> What's missing?  ...a return route!!!
> 
>    So on the JNOS/Hamgate I have to add a route that will send any packets
> it receives *for* 44.102.1.239 *back* to the Linux box on the ethernet.  
> So on the JNOS/Hamgate I have added this route:
> 
>    route add 44.102.1.239 eth0

this was:
   route add 44.102.132.229 tun0

The route tables partly worked - the packet went out.

> 
> 
>    BINGO!!!  

NO BINGO!!!  Lost packets for wrong FROM IP (I guess).


>    Skip, I believe you will be attending this Saturday's DRG meeting?  In
> my training session I'll be going over static routing and how to "Think
> like a Packet".  Hope to see you there!  And hope that we can help clear
> up any misconceptions and help lift the fog a little.  I'll bring an empty
> V8 juice can with me so you can smack it into your forehead when this all
> comes clear for you ;-)  See you there!

I expect you will see me - but I'd like to be successful before I arrive
at the meeting.

What say you?

> 
>       --- Jay Nugent  WB8TKL
>  



73
de [George (Skip) VerDuin] K8RRA k
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Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
k8rra.ampr.org  *               255.255.255.255 UH    0      0        0 tun0
192.168.1.0     *               255.255.255.0   U     0      0        0 eth0
169.254.0.0     *               255.255.0.0     U     0      0        0 eth0
44.102.0.0      *               255.255.0.0     U     0      0        0 tun0
default         192.168.1.254   0.0.0.0         UG    0      0        0 eth0