[PLUG] Two hosts: lo address and route issues

[Louis Kowolowski]

I don’t see anything here that suggests your problems have anything to do with DNS.

It appears that you have (likely) layer3 connectivity issues. I’m going to assume that you’re using a known functional ethernet cable and you get a link-up (either lights on devices, or ifconfig shows the interface UP). 
I suspect that you’ve misconfigured the IP address and or netmask for the interface (I’m talking about ethernet, not loopback. its very unlikely that you need to change anything loopback related, unless you’ve already changed it, in which case you should change it back).

if the network device supports DHCP, you should use that. If not, you’ll need to know what IP block you should use to be able to connect to the network device. Until you get this sorted, nothing else will work.


> On Dec 18, 2019, at 2:24 PM, Rich Shepard <rshepard at appl-ecosys.com> wrote:
> 
> Attempting to tweak the configuration of the ER-X (port eth1) using the Dell
> 2100 (interface eth0) I'm encountering loopback address and routing issues
> that I've not fixed using ip.
> 
> When the laptop boots 'ip link show' has only 127.0.0.0/8 (the loopback
> interface) when I expected it to have 127.0.0.1/24.
> 
> Running 'ip link set eth0 up' brought up the eth0 interface. Then 'ip route 192.168.55.3 via 192.168.55.4 dev eth0' returns
> RTNETLINK answers: network is unreachable
> (When I change the interface address to 192.168.55.3/24 RTNETLINK answers
> 'Invalid argument'.)
> 
> My understanding is that this is a DNS lookup issue. The laptop's
> /etc/resolv.conf contains:
> 
> nameserver 8.8.8.8
> nameserver 127.0.0.1
> nameserver 192.168.55.1
> 
> Because the laptop is not connected to the LAN, only to the ER-X, I expected
> the loopback address would work, but ip is not seeing that address for some
> reason I've not before encountered.
> 
> # ip r show
> # 127.0.0.0/8 dev lo
> 
> What I want to do is change adminname and password, adjust the DHCP range,
> and upgrade the OS to 2.0.8 yet I have apparently hit the edge of my
> networking knowledge in trying to both fix the lo IP address and establish
> communications with the ER-X so I can make the changes.
> 
> Looking forward to expanding my network knowledge.
> 
> Regards,
> 
> Rich
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Louis Kowolowski                                louisk at cryptomonkeys.org <mailto:louisk at cryptomonkeys.org>
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