[Novalug] route not set up on eth0

Stephen Cicirelli scicirelli@gmail.com
Wed Dec 21 23:54:47 EST 2016


I don't know what else is going on with this system but the output
from ifconfig of eth0 doesn't show an IPv4 address being bound to the
nic, so I don't know why anyone is expecting it to be able to ping ANY
IPv4 address.

It shows an IPv6 address that appears to be the link local address and
is not configured to speak to the world either.

On Wed, Dec 21, 2016 at 10:56 PM, Peter Larsen via Novalug
<novalug@firemountain.net> wrote:
> On 12/21/2016 05:02 PM, Walt Smith wrote:
>> The wireless 4 port switch  had some kind of problem not
>> obvious to me.  On the CentOS6, at the end of eth0,  the
>> 4 port switch/router 192.168.1.1 would not respond with a
>> general route of 192.168.1.0 using ping.
>
> As I've explained a few times here in the group and in private, this
> makes no sense!!  You're NOT routing when accessing a subnet to which
> you belong. At least not in the sense you've described. The fact that
> your ARP is working means you have connection to this line, and it means
> your "route" is working. All the route is doing is telling the OS that
> all IP traffic to 192.168.1/24 is to be passed to eth0. The rest is up
> what's on the other end of that cable.
>
> A route problem would be that traffic is sent to the wrong interface and
> hence gets lost.
>
> So I again ask you to restate the problem. If you are unable to ping a
> static IP on a router, based on your own static IP setup, you'll start
> by verifying the setup on both sides. So far, I've not seen a single
> post where you dump the setup on the router - you just keep telling that
> it's on IP 192.168.1.1 - but you never mention subnet or anything else.
>
> For consumers, this is pretty straight forward. They take their router,
> plug in a power cable, and a single RJ45 into the "client" side of the
> router, and the other end of that cable into a NIC in the computer. Turn
> on the router and b y default, the computer will use dhcp on the
> interface if properly installed, and hence the computer will get all the
> correct settings for IP, network, gateway etc. That of course assumes
> the consumer doesn't have any other networks connected.  But I would
> start there and simplify.
>
> To have two systems talk to one another via layer 3, they MUST be in the
> same subnet. Without that prereq nothing else will work.  Then there are
> firewalls and other mechanisms that control what a node/device should
> respond to. Generally speaking, a default router should NOT firewall
> anything but it's always good to verify. A firmware reset will
> definitely take care of this. And note, you can have firewalls on BOTH
> sides here which may block ICMP and other protocols.
>
> Here's what I would do:
>
> 1) Drop your modem connection
> 2) Connect your PC to the router using a simple cat5 cable, and plug it
> into the "client" port on the router (not the uplink).
> 3) Perform a firmware reset of the router (assuming you're the only one
> connected to it)
> 4) Enable dhcp on your PC - this is DEFAULT - just make sure
> BOOTPROTO=dhcp in /etc/sysconfig/network-scripts/ifcfg-eth0 - reset your
> network service and the rest is automatic. You should get an IP address,
> and you should be able to ping the router. Or using nmcli: nmcli c
> modify eth0 ipv4.method dhcp
> 5) Once you have it pinged, head to a browser and hit the IP of the
> router using just http - that will get you a username/password prompt -
> and your manual will tell you what the default user/password is. Login
> and check the parameters.
>
> If you're having problems with this setup, it's something physical. If
> you cannot reset the firmware, then it's most likely because you don't
> have the right information about the setup of the router.
>
> Once you're at this point, you can start making things more complex like
> using PPP and your router at the same time, or if you insist change the
> defaults for the network parameters on the gateway - make those, test
> them before you connect your PPP etc. The only thing activating PPP will
> do after you've setup your eth0 address with dhcp is overwrite your
> default gateway and DNS. Most likely that's what you want anyway so you
> can browse the internet etc.
>
> NOTE - eth0 is a WIRED connection. If you have a wireless router, you
> cannot use your wired connection to connect to wireless devices UNLESS
> they're already associated with the router and connected with an IP. The
> Wireless Router (AP) is NOT a client - it's a server.
>
> --
> Regards
>   Peter Larsen
>
>
>
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