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Bumped by Community user
Bumped by Community user
Bumped by Community user
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tkalay
tkalay
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EDIT 1: Using xterm in the namespace, indeed makes testing easier.
I also started to using

dhclient -d enx8cae4cff1c86

instead of DHSCP server in namespace.
However problem continues.I am thinking this is somewhat due to routing. Following is result of route command from interfaces outside of namespace

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         router.asus.com 0.0.0.0         UG    303    0        0 wlp3s0
10.11.1.0       0.0.0.0         255.255.255.0   U     303    0        0 wlp3s0
10.18.0.0       0.0.0.0         255.255.255.0   U     0      0        0 enp0s25
10.18.0.0       0.0.0.0         255.255.255.0   U     100    0        0 enp0s25

and this one from namespace

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         10.1.1.1       0.0.0.0         UG    0      0        0 enx8cae4cff1c86
10.11.1.0       0.0.0.0         255.255.255.0   U     0      0        0 enx8cae4cff1c86
10.1.1.0       0.0.0.0         255.255.255.0   U     0      0        0 enx8cae4cff1c86

Any suggestions about possible modifications to routing in namespace?

EDIT 1: Using xterm in the namespace, indeed makes testing easier.
I also started to using

dhclient -d enx8cae4cff1c86

instead of DHSCP server in namespace.
However problem continues.I am thinking this is somewhat due to routing. Following is result of route command from interfaces outside of namespace

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         router.asus.com 0.0.0.0         UG    303    0        0 wlp3s0
10.11.1.0       0.0.0.0         255.255.255.0   U     303    0        0 wlp3s0
10.18.0.0       0.0.0.0         255.255.255.0   U     0      0        0 enp0s25
10.18.0.0       0.0.0.0         255.255.255.0   U     100    0        0 enp0s25

and this one from namespace

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         10.1.1.1       0.0.0.0         UG    0      0        0 enx8cae4cff1c86
10.11.1.0       0.0.0.0         255.255.255.0   U     0      0        0 enx8cae4cff1c86
10.1.1.0       0.0.0.0         255.255.255.0   U     0      0        0 enx8cae4cff1c86

Any suggestions about possible modifications to routing in namespace?

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tkalay
tkalay
  • 41
  • 1
  • 5

Internet connectivity using linux network namespace

I experimenting with Linux namespaces on Ubuntu 17.1 distro. Ultimate goal is to force an application to use a particular network interface via a 3G modem not the intranet wired connection. My PC has 3 network interfaces.

enp0s25: wired to a intranet router w/o internet connectivity
inet 10.18.0.101

wlp3s0: wireless, used for remote management, will not be available in production environment
inet 10.11.1.116

enx8cae4cff1c86: wired, simulating a 4G USB mobile modem eventually will be used in production environment
inet 10.11.1.142

wlp3s0 and enx8cae4cff1c86 are connected to the same router.I have used following code to created a name space called mobilens

ip netns add mobilens
ip link set dev enx8cae4cff1c86 netns mobilens
ip netns exec mobilens ifconfig enx8cae4cff1c86 10.1.1.10/24 up
ip netns exec mobilens ifconfig lo 127.0.0.1/8 up
ip netns exec mobilens route add default gw 10.1.1.1
ip netns exec mobilens dhcpcd enx8cae4cff1c86

I have also created a /etc/netns/mobilens/resolv.conf file with following entries

nameserver 10.11.1.1
nameserver 8.8.8.8
search google.com

Running ifconfig in name space with

ip netns exec mobilens ifconfig

returns
inet 10.1.1.10 netmask 255.255.255.0
and if I query DNS servers used in namespace as follows

ip netns exec mobilens nmcli dev show | grep DNS

it returns

IP4.DNS[1]: 10.11.1.1

I try to ping google.com using this namespace it resolves but fails.

ip netns exec mobilens ping www.google.com

PING www.google.com (172.217.7.4) 56(84) bytes of data.
From 10.1.1.10 (10.1.1.10) icmp_seq=1 Destination Host Unreachable
From 10.1.1.10 (10.1.1.10) icmp_seq=3 Destination Host Unreachable

What else I need to do to be able to access to internet via this namespace?