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Bug 1597691

Summary: Network configuration not fully updated when switching to DHCP
Product: Red Hat Enterprise Linux 7 Reporter: Thibault <tr>
Component: kde-plasma-networkmanagementAssignee: Jan Grulich <jgrulich>
Status: CLOSED ERRATA QA Contact: Desktop QE <desktop-qa-list>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.5CC: atragler, bgalvani, bsanford, fgiudici, lrintel, mboisver, rkhan, sukulkar, thaller, tpelka, tr
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: kde-plasma-networkmanagement-0.9.0.9-8.el7 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-09-29 19:26:06 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Thibault 2018-07-03 12:47:15 UTC
Description of problem:

On a machine static ip configured machine (from kde plasma network manager applet). When switched back to DHCP, the ifcfg-XXX file is not updated correctly.

Version-Release number of selected component (if applicable):
NetworkManager 1.10.2-14.el7_5


How reproducible:


Steps to Reproduce:
1. Configure your network connection with a static IP in the Network Manager Applet and restart network services

# systemctl restart network.service

2. check your config file

# cat /etc/sysconfig/network-scripts/ifcfg-enp3s0
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=no
IPV6_AUTOCONF="yes"
IPV6_DEFROUTE="yes"
IPV6_FAILURE_FATAL="no"
IPV6_ADDR_GEN_MODE="stable-privacy"
NAME=enp3s0
UUID=e327ceec-9e06-4fe0-a550-78031c21f5cf
ONBOOT=yes
ZONE=public
IPADDR=10.0.0.100
PREFIX=24
GATEWAY=10.0.0.1
DNS1=10.0.0.254
DOMAIN=mydomain.com

3. edit your config to switch to DHCP in the network manager applet
4. restart network service and check your IP address

# systemctl restart network.service

# ifconfig enp3s0
enp3s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.111.11  netmask 255.255.255.0  broadcast 192.168.111.255
        inet6 fe80::210:18ff:fe31:7d95  prefixlen 64  scopeid 0x20<link>
        ether 00:10:18:31:7d:95  txqueuelen 1000  (Ethernet)
        RX packets 636030  bytes 868320403 (828.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 170755  bytes 13408339 (12.7 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 17

but network is not accessible.
Then when you check your config file

# cat /etc/sysconfig/network-scripts/ifcfg-enp3s0
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=no
IPV6_AUTOCONF="yes"
IPV6_DEFROUTE="yes"
IPV6_FAILURE_FATAL="no"
IPV6_ADDR_GEN_MODE="stable-privacy"
NAME=enp3s0
UUID=e327ceec-9e06-4fe0-a550-78031c21f5cf
ONBOOT=yes
ZONE=public
IPADDR=10.0.0.100
PREFIX=24
GATEWAY=10.0.0.1

Actual results:

The old IP is still there.

Expected results:

It should not be there...

Additional info:

Edit your ifcfg-xxxx file, restart network service to fix that.

Same issue when using nmcli to configure the network interface

Comment 2 Beniamino Galvani 2018-07-05 12:37:47 UTC
(In reply to Thibault from comment #0)
>
> ...
> Same issue when using nmcli to configure the network interface

Can you paste the nmcli commands you used, the initial state (output of "nmcli c; nmcli d; ip a") and the final state (same command)? Please also note that when a connection is modified, changes are applied only after a reactivation of the connection. So, after the 'nmcli connection modify ...' command you need also to call 'nmcli connection up <con>'.

Comment 3 Thibault 2018-07-05 13:22:11 UTC
Here is what I did but I'm not a specialist of this tool.

nmcli con down enp3s0
nmcli con mod enp3s0 ipv4.method static ip4 10.0.0.10/24 gw4 10.0.0.1 ipv4.dns 10.0.0.254
nmcli con up enp3s0
nmcli con mod enp3s0 ipv4.method auto
nmcli con down enp3s0 && nmcli con up enp3s0

Comment 4 Beniamino Galvani 2018-07-06 07:35:50 UTC
(In reply to Thibault from comment #3)
> Here is what I did but I'm not a specialist of this tool.
> 
> nmcli con down enp3s0
> nmcli con mod enp3s0 ipv4.method static ip4 10.0.0.10/24 gw4 10.0.0.1
> ipv4.dns 10.0.0.254
> nmcli con up enp3s0
> nmcli con mod enp3s0 ipv4.method auto

Setting "ipv4.method auto" does not automatically clear the static addresses in the connection and so you end up with:

 ipv4.method auto
 ipv4.addresses 10.0.0.10/24

You can see this with "nmcli connection show enp3s0". Therefore, when the connection gets activated both the dynamic and static addresses are applied.

The command should be:

 nmcli con mod enp3s0 ipv4.method auto ipv4.addresses ""

if you want only the DHCP address.

> nmcli con down enp3s0 && nmcli con up enp3s0

Comment 5 Thibault 2018-07-06 07:40:24 UTC
thanks for the explanation with nmcli.
But then the problem persists with the KDE Network Applet

Comment 6 Beniamino Galvani 2018-07-06 07:59:51 UTC
Do you clear the static address when switching from Manual to DHCP addressing using the KDE Network Applet?

Comment 7 Thibault 2018-07-09 11:03:39 UTC
No, I just opened the panel, and changed the "select" menu from manual to automatic. For me, it should reset everything and switch to DHCP.

Comment 14 errata-xmlrpc 2020-09-29 19:26:06 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (fltk bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:3872