[SOLVED] Unable to reach Internet during installation

amcooper · 2020-09-27 01:58:29

I am trying to install Arch Linux on a partition of my MacBook Pro from a USB stick. I intend to start the process with an Ethernet connection to the Internet. When I boot from the stick, and run ip link, I see enp0s20u2, and it's up. I then proceed as follows:

root@archiso ~ # ip address
1: lo: [...snip...]
2: enp0s20u2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 disc fq_code1 state UP group default qlen 1000
    link/ether 00:0e:c6:64:ee:a3 3rd ff:ff:ff:ff:ff:ff
    inet6 fe80::20e:c6ff:fe64:eea3/64 scope link
       valid_lft forever preferred_lft forever
root@archiso ~ # ip route
root@archiso ~ # dhcpcd
dhcpcd-9.1.4 starting
dev: loaded udev
DUID: 00:04:35:ec:72:41:40:15:80:56:b1:16:e1:eb:9a:bb:34:0c
enp0s20u2: IAID c6:64:ee:a3
soliciting an IPv6 router
soliciting a DHCP lease
offered 192.168.100.19 from 192.168.100.1
NAK: requested address not available from 10.0.1.1
message: requested address not available
soliciting a DHCP lease
offered 192.168.100.19 from 192.168.100.1
NAK: requested address not available from 10.0.1.1
message: requested address not available
soliciting a DHCP lease
offered 192.168.100.19 from 192.168.100.1
ignoring offer of 10.0.1.9 from 10.0.1.1
NAK: requested address not available from 10.0.1.1
message: requested address not available
[...]

It continues with that extra 'ignoring' line indefinitely.

It looks like it's not getting an IPv4 address at first, and then when it tries, it struggles and fails. I'm not totally new to Arch but am not knowledgeable about networking, so I'd appreciate any help anyone can offer. Thanks!

Last edited by amcooper (2020-09-30 20:01:41)

fukawi2 · 2020-09-27 02:34:09

What subnet do you expect an address to be given on? It looks like a DHCP Server at 192.168.100.1 is offering you an address in that space, but another DHCP server at 10.0.1.1 is blocking that lease.

amcooper · 2020-09-27 15:07:19

[Edited] I only ever see an address between 10.0.1.2 and 10.0.1.7. The Airport Utility says the range is 10.0.1.2 to 10.0.1.200.

Last edited by amcooper (2020-09-27 15:15:19)

seth · 2020-09-27 17:38:18

There must however be a second subnet and a rogue dhcp server… maybe a guest network?

Is dhclient available on the install iso?
Try

dhclient -s 10.0.1.1

amcooper · 2020-09-28 22:45:11

I have a primary wireless network and a guest network on the router, a Time Capsule, but Arch doesn't see any wireless networks on boot, just the Ethernet network.

I ran `dhclient -s 10.0.1.1`; it ran silently for 60 seconds until I hit Ctrl-C. Running `journalctl | grep dhclient` yielded the following:

archiso ~ # journalctl | grep dhclient
dhclient[719]: DHCPDISCOVER on enp0s20u2 to 10.0.1.1 port 67 interval 4
dhclient[719]: DHCPOFFER of 192.168.100.21 from 192.168.100.1
dhclient[719]: DHCPREQUEST for 192.168.100.21 on enp0s20u2 to 10.0.1.1 port 67
dhclient[719]: send_packet: Network is unreachable
dhclient[719]: send_packet: please consult README file regarding broadcast address.
dhclient[719]: dhclient.c:2855: Failed to send 300 byte long packet over fallback interface.

And then it repeats, more or less (let me know if more detail is helpful here, and I'll type out the whole thing).

fukawi2 · 2020-09-29 00:44:16

You're still getting a DHCPOFFER from 192.168.100.1 - what is that? You shouldn't have 2 DHCP servers on the same network, it will cause all sorts of problems for you beyond this.

seth · 2020-09-29 06:08:01

The server on 10.0.1.1 seems configured for 2 subnets and responds the 192.168.100.0/24 on dhcp requests (the dhclient option makes it ask that specific IP instead of a broadcast, so it must be the same physical server)
Look at the router config, but my guess is that 192.168.100.0/24 is your guest network and it bleeds into the private one. You want to fix that.

amcooper · 2020-09-30 19:57:55

As a FIOS n00b, I mistakenly still had the modem connected to the router. This didn't perceptibly interfere with Internet access, even on MacOS via Ethernet-USB, until trying to connect from ArchISO. But disconnecting them seems to have done the trick. Thanks, @seth & @fukawi2!

fukawi2 · 2020-10-01 00:00:08

Two DHCP servers will create all kinds of weird and inconsistent issues depending on timing (ie, the order packets to/from each server reaches the client), and individual implementations of the DHCP Clients.

Glad you sorted it out!

Arch Linux

#1 2020-09-27 01:58:29

[SOLVED] Unable to reach Internet during installation

#2 2020-09-27 02:34:09

Re: [SOLVED] Unable to reach Internet during installation

#3 2020-09-27 15:07:19

Re: [SOLVED] Unable to reach Internet during installation

#4 2020-09-27 17:38:18

Re: [SOLVED] Unable to reach Internet during installation

#5 2020-09-28 22:45:11

Re: [SOLVED] Unable to reach Internet during installation

#6 2020-09-29 00:44:16

Re: [SOLVED] Unable to reach Internet during installation

#7 2020-09-29 06:08:01

Re: [SOLVED] Unable to reach Internet during installation

#8 2020-09-30 19:57:55

Re: [SOLVED] Unable to reach Internet during installation

#9 2020-10-01 00:00:08

Re: [SOLVED] Unable to reach Internet during installation

Board footer