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Old 04-15-2017, 04:11 AM   #1
Registered: Dec 2006
Location: Bucharest
Distribution: Ubuntu 16.04 LTS
Posts: 103

Rep: Reputation: 13
why eth1 with auto dhcp disturbs pppoe over eth0

Hi, I use ubuntu 16.04 desktop with ufw (default setup + 22, 80, 443 ports open).

I connect directly to ISP using pppoe over eth0. I also have eth1 which when disabled the websites are accessible in browser. When starting eth1 with auto dhcp the websites are no longer accessible in browser (give a timeout while trying to load). eth1 is plugged in a LAN port of a router with its WAN port unplugged (yeah, don't ask why). When setting a manual ip on eth1 while gateway and dns are left blank the websites are accessible in browser again.

Why this happens?

Last edited by adrhc; 04-15-2017 at 03:06 PM.
Old 04-15-2017, 04:46 PM   #2
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Registered: Dec 2003
Location: The Key Stone State
Distribution: CentOS Sabayon and now Gentoo
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I'm willing to bet when you turn on your eth1 it over writes the default GW thus making your system not able to connect to the internet.

Can you give us the output of
route -n
when eth1 is turned off and then again when eth1 is turned on?
Old 04-15-2017, 04:56 PM   #3
Registered: Dec 2006
Location: Bucharest
Distribution: Ubuntu 16.04 LTS
Posts: 103

Original Poster
Rep: Reputation: 13
Interesting idea; I'll give it a try when I'll be back home (after Easter).


dhcp, lan, pppoe, ubuntu 16.04

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