On 9 Nov 2006, in the Usenet newsgroup comp.os.linux.misc, in article
Usenet newsgroup comp.os.linux.networking, in article
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Quote:> I have a strange problem with my home network.
>It all used to work before but I disconnected everything and reconnected
>them again and now everything is ok with the exception that I cannot
>ping my internal network.
Is it just ping, or all networking? "What did you change?"
Quote:>Eth1 = internal interface (static) ip=192.168.1.2
>iptables setup unchanged - I run an iptables firewall on my PC
>I used firestarter to setup the firewall which works fine for forwarding
Quote:>Eth1 connects to a linksys WRK54G home wireless router, via a cable.
>The home router is 192.168.1.1 and I recently set it to factory defaults.
>I have set its default gateway to be 192.168.1.2 ( Eth1 on PC )
Quote:>2 laptops (running windows XP) access the wireless router to connect
>to the internet, ofcourse via my linux PC gateway.
The router would have to be in transparent bridge mode for that to work.
What are the addresses of the two laptops?
>Now, when I start a dhcp server on the linksys router and use dhcp
>clients on the laptops, I get connectivity. I also get connectivity if
>I dont use a dhcp server on the linksys and set up static ip on laptops
>using default gateway 192.168.1.1
>But in either cases I have to set up a route to 192.168.1.2 via 192.168.1.1
>on the laptops.
Smells like the problem.
>The linux PC cannot ping nor ssh into the laptops (cygwin sshd). Though
>this used to work before!
What did you change? I suspect the laptops are using the same 192.168.1.x
network range, but the router is not acting as a transparent bridge. The
result is that the laptops and the linux box think that because the network
number and network mask are the same, they can each talk _DIRECTLY_ to the
other, and don't have to use the router. If you use a packet sniffer, you'd
likely see the Linux box sending ARP requests to the laptops ("where are you
little lap-doggy?"), and the router is not Proxy-arping ("I'm here"), or not
forwarding the ARP packets to the laptops and vice versa.
Quote:>I tried to setup a static route from the linux pc to the laptop to no
How? Did you also try this the same time you told the laptop to send
everything for the Linux box via the router?
Quote:>I get no route to host when I use ssh and host unreachable when i use
>ping. ALL THIS even if iptables is turned OFF.
Routing issue, not firewall.
Quote:>Plus I've noticed a strange 169.254.0.0 or something like that in the
169.254.0.0/16 is the network used for "ZeroConf" - originated by Apple as
the "Rendezvous", renamed as "Bonjour", and adopted by microsoft as a means
to get networking running when the MCSE has so screwed up the configuration
of the DHCP server that even windoze can't run. Some Linux distributions
have added a route for that network so that packets with that range as a
source are not logged as "Martians". If you see packets from that network,
some box is configured to get addresses from DHCP, but can't find a DHCP
server. As we use static addresses, we alarm if one of those addresses is
seen, as that means we have an intruder on our wires.
Quote:>Can anyone help with any suggestions on how to
>1) Not have to manually add a static route to 192.168.1.2 on the
>2) How to make my PC ping and talk to my laptops
Two choices - change one or the other network address, so that the Linux box
and lap-doggies know they are on different networks, and have to send packets
to the router for onward transmission, OR configure the WRK54G to bridge
the packets. Adding host routes via the gateway would also work, but is