almost OT os x

[Jeremy Chadwick]

On Mon, Oct 27, 2008 at 10:19:56PM -0400, kalin m wrote:
> this is a bit OT but since bsd and os x have enough in common in the  
> core some people here might have dealt with an os x server before..
>
> ok. here is the problem. i have this os x server put on my lap to  
> administer and there are some really weired things happening.
>
> the machine has 2 inet interfaces - 2 cards. one of them - en0 (network  
> A) - is wired to 192.168.x.x and the other - en1 (network B) - has an  
> external ip which is not on the same subnet (network)  the 192.168.x.x  
> belongs to. so far so good.
>
> theoretically the en1 (network B) card should be accessible through the  
> external ip no matter where you a coming from....
>
> what happens is that if somebody on network A (of en0)  tries to access  
> the machine via 192.168.x.x - it works. but if that somebody wants  
> access that machine via the external ip on network B (en1), like they  
> would access any other external IP -  they can not. this is weired  
> because they can access any other machine on B . now me being on the  
> network B i can access the machine via the external IP which is also on  
> B, but, and this is the weirdest, i can not access it from outside  
> either A or B with that same IP (?!?).  but i can access any other  
> machine on B from outside either subnet....   

What you're describing sounds like a network loopback problem (at least
this is what the Linux folks refer to it as).

I would recommend you re-post this question to freebsd-net, as someone
there can explain to you what's happening in detail, why it happens, and
how to solve it effectively.

Also, keep in mind that the "FreeBSD and OS X have enough in common"
concept is a horrible one -- they do have some pieces in common, but
OS X really *is* quite a different beast in numerous respects.  Apple,
sincerely and honestly, has tinkered with all sorts of pieces.  Please
keep that in mind.  :-)

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |