Web lists-archives.com

Re: Wan/Lan problem

On March 28, 2017 7:46:02 PM EDT, Mike McClain <mike.junk.46@xxxxxxxxxx> wrote:
>I have a WAN/LAN challenge I'm hoping for help with.
>I'm runniing Debian 7.11 on a Pentium 3 with 250MB ram.
>mike@/deb7:~> uname -a
>Linux playground 3.2.0-4-686-pae #1 SMP Debian 3.2.84-2 i686 GNU/Linux
>The situation is this:
>     phone        eth0         eth1
>AT&T-------|   |--------|   |--------|   |-------|   |
>        AT&T modem/     Linux         my         Win2K
>            router       box         router       box
>When eth0 is up and eth1 down,
>                    the Linux box can access the web.
>                    'ping ATTrouter' works.
>When eth0 is up and eth1 up,
>                    the Linux box can not access the web.
>                    the Win2K box can access the web.
>                    the Linux box can not access the Win2K shares.
>                    'ping ATTrouter' fails.
>                    'ping -Ieth0 ATTrouter' works.
>When eth0 is down and eth1 up,
>                    the Linux box can access the Win2K shares.
>When eth0 is down and eth1 down,
>                    it's quiet.
>The ATT router is set to 'Pass Through' giving the Linux box the ATT
>router's IP address.
>The Linux box is set to use DHCP.
>This might explain why I loose the LAN connection when eth0 up.
>Why can the Linux box not see the web while the Win2K box can?
>I've not found or at least recognized the problem in the HowTo's.
>Pointer's or suggestions?
>#   /etc/hosts
>    ATTrouter
>#    outbound.att.net    att
>       localhost
>     playground      play
>     south40         s40
>     router
># ----------------------- end hosts
># /etc/networks
># ----------------------- end networks
># /etc/resolv.conf
>domain attlocal.net
>search attlocal.net
># ----------------------- end resolv.conf
>#   /etc/network/interfaces
># This file describes the network interfaces available on your system
># and how to activate them. For more information, see interfaces(5).
># The loopback network interface
>auto lo
>iface lo inet loopback
># The primary network interface
>allow-hotplug eth1
>#   eth0 = onboard eth port
>iface eth0 inet dhcp
>#   eth1 = 3Com PCI 3c905C card
>iface eth1 inet static
>        address
>        netmask
>        network
>        broadcast
># dns-* options are implemented by the resolvconf package, if installed
>        dns-nameservers
># ----------------------- end interfaces
>"I reckon some folks figure it a compliment to be called
>Back home, broad-minded is just another way of saying a feller is too
>lazy to form an opinion."    - Will Rogers

You put eth0 and eth1 into the same network segment.
That most likely is your problem
Either you bridge eth0 and eth1 or if you want your linux box as a firewall you pick a different ntwork for eth1

Henning Follmann