[clug] Local Mail Howto

Keith Goggin keith.goggin at bigpond.com
Sun May 9 22:11:15 MDT 2010


Daniel Rose wrote:

Hi Daniel,

> We have to be careful not to assume stuff.  There's not really such a
> thing as an IP 'alias' in that sense; even if you have multiple IPs on
> the same interface, they can still behave differently, different
> routing, firewalls or listening services, for example.The wired network is
>   
Yes I have made assumptions here. The problem is I have no knowledge of 
networks beyond the most basic of home networks. In this environment it 
is easy to make the wrong assumptions, particularly if they seem to work.
> Okay, so the Telstra box is running seperate subnets for wired and
> wireless.  That's atypical, usually these things just bridge the all the
> local interfaces.  If it were me I'd be looking for a setting in the web
> interface to ensure that these are bridged.  Can you confirm that the
> Telstra gateway acts as a DHCP server on both interfaces, or are you
> running one?  Can you find anything in the web interface that looks like
> it might let you control the routing, bridging or firewalling between
> the two segments?  You might be able to get help from Telstra for this
> sort of thing as well, since it's their box.
>
>   
Again my fault entirely, the bigpond/netcomm 3G9WB has a distinct 
configuration preference for it's default subnet (10.0.0.n) and the  
linksys WVC54G has the same bias towards it's default subnet 
(192.168.1.n). I thought the 3G9WB's ability to 'Configure the second IP 
Address and Subnet Mask for LAN interface' was a neat solution to this 
problem and it still may be. It's just that I'm a bit out of my depth 
with dual subnets and Bridge mode.

I thought Bridge mode was a technique to connect two pc's to the net 
without a router/switch/hub.
   
   PC---------PC---------Modem

The 3G9WB does have configuration screens for routing and Bridging.

The Routing screen refers to:-

Destination Network Address:
Subnet Mask:
Use Gateway IP Address:
Use Interface (ppp0/ppp0 or LAN/br0)

and the Wi-Fi Bridge screen refers to:-

AP Mode: (Access Point/Wireless Bridge)
Bridge Restrict: (Enabled/Enabled Scan/Disabled)

Firewalling is controlled by the Security IP Filtering Outgoing and 
Incoming screens.

As for the 3G9WB acting as a DHCP server on both interfaces I don't know 
but I'm not running an independent DHCP server.

Unfortunately my Router is branded and supplied by Bigpond not Telstra 
who have an identical model 3G9WT IIRC, Telstra don't provide tech 
support to Bigpond customers and v.v. Bigponds customer support is based 
in the Philippines and is considerably less than basic.

> Failing this, you need to pretend to be the camera.  Get a wifi device;
> a laptop or eeepc or something.  Get on the wifi with that and see if
> you have dns and can telnet to the mail host on port 25.
>
>   
Yes this is a great idea thanks, I'll see if I can borrow one from a mate.
> If you don't want to or can't get another node on the wifi LAN, then you
> can either get another wifi router, disable the DHCP server in that,
> shut off the wifi on your telstra gateway and connect any NON-Internet
> port on the new wifi box to a 10.0.0 port on the telstra box.  Then
> you'll find your camera will be picking up a 10.0.0.x address, which
> might make things easier but does not guarantee instant success.
>
> You could also try configuring the camera to send to a "real" Internet
> address, instead of the local mail host addresses you mentioned
> earlier.  These last two are workarounds though and don't really give
> you the solution you were originally after.
>
>   
I have tried this one but no joy. Must add local mail to my list of 
relevant incompetencies. I could claim that is implied by my subject 
line:-)
> Good Luck!
>   
Thanks I'll need it.



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