Home Network Setup Problem

Greg Barniskis nalists at scls.lib.wi.us
Fri Sep 9 07:56:03 PDT 2005


deltaski at earthlink.net wrote:
> Thank you all, who have considered this message!
> 
> I am learning BSD with 3 successful units. 1-100mhz pent. running 4.11
> 1-180mhz pent. running 5.4 and one 266mhz AMD running 5.4
> 
> I have learned the ins and outs of X, changing rc.conf and am quite good
> at reinstalling the system after a few "learning" adjustments.
> 
> Just for fun and my own enjoyment in learning, I have now accepted the 
> challenge of my own home network. I have been able to connect all boxes to my 
> DSL router with DHCP and manual IP assignments and changed/setup NIC's with 
> ifconfig. My reference materal is the Handbook from FreeBSD.org and "The 
> Complete FreeBSD" by Greg Lehey.
> 
> Now the problem!
> 
> DSL is 192.168.1.1 - Box B has two NIC's rl0=192.168.1.100 netmask 
> 255.255.255.0 and is connected only to 192.168.1.1 ping works/outside 
> internet works.
> Box B second NIC rl1=172.16.1.1 netmask 255.255.255.0 and is connected to a 
> standalone switch/router. 

Is it a switch, is it a router, or is it really both (high end 
thingy like Cisco 35xx?). Probably it is just a plain old switch 
with no routing capabilities. To avoid confusion, you should call it 
what it is.

> Box A has one NIC eth0=172.16.1.35 and is connected to the standalone 
> switch/router. Box A can ping 172.16.1.35 and 172.16.1.1 on box b. It can NOT 
> ping 192.168.1.1 or access any outside internet.
> 
>>From Box B keyboard, I can ping 
> 192.168.1.1/192.168.1.100/172.16.1.1/172.16.1.35
> 
>>From Box A keyboard, I can ping only 172.16.1.35/172.16.1.1
> 
> I have tried ifconfig rl0 192.168.1.100 172.16.1.1 netmask 255.255.255.0 among 
> many other configurations without success.
> 
>>From my reading, I think the error of my ways is in the Box B between nic rl0 
> and rl1. The data packets are not being forwarded from rl1 to rl0 or rl0 to 
> rl1. Somewhere I have missed something. If anyone could point me in the 
> correct direction, it would be greatly appreciated.

At a guess, I think what you are missing is to put

gateway_enable="YES"

into rc.conf of box B (between the Internet router and the inside 
network switch). Otherwise it will not hand packets from one network 
to another. However, you probably do NOT want to enable that without 
also enabling and configuring firewall features on this box as well, 
for which I will refer you to RTFM (the Really Tremendously Fine 
Manual ;).

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/firewalls.html

If you already have gateway and firewall functions going, does the 
inside box (A) have box B's 172 addr set as its default gateway 
router? If not, then it does not know to send packets destined for 
other networks in that direction for processing. If yes, is your 
firewall configured so tight that it's killing the packets you'd 
like to forward?

-- 
Greg Barniskis, Computer Systems Integrator
South Central Library System (SCLS)
Library Interchange Network (LINK)
<gregb at scls.lib.wi.us>, (608) 266-6348


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