[Server-devel] A quick networking question

Holt holt at laptop.org
Tue Feb 28 12:49:34 EST 2012

On 2/28/2012 12:29 PM, George Hunt wrote:
> In Haiti, Adam and I have been trying to get a school server online.  
> We're finding that volunteers are going through the school server to 
> the internet with their laptops, and he wants to turn that off, at 
> least for now.
> I've turned off /proc/net...ip_forward and verified that there is no 
> masquerade enabled in the iptables.
> But that's not enough!!  I wasn't sure that the vpn wasn't setting up 
> a gateway, so I had him turn off the vpn.  But still the school server 
> was routing to the 3G usb modem dongle even with the vpn pipe closed 
> down.
> How does the school server act like a router?  It may be related to 
> the ppp connection and wdial configuration.  But I'm stumped.
> But I'm trying to bring myself up to speed quickly because he really 
> wants to get it turned off.
> Any ideas on what to try next?  I'm afraid the solution is going to be 
> to pull out the 3g dongle.

Interestingly the XS(*) creates an open path for any random non-XO 
laptop to access the web, but seems to block non-web traffic like ssh 
and IMAP.

In any case, even if it's just forwarding port 80 and 443 (?) we just 
cannot afford to become a free ISP here in semi-rural Haiti, given so 
many visitors to our school especially.

     (*) XS as set up by Tony Anderson early autumn 2011, and currently 
maintained by George Hunt & I.

Help kids everywhere map their world, at http://olpcMAP.net !

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