I want to setup an IP address alias on a Network card. I created a file /etc/sysconfig/network/ifcfg-ens160:0 and file contents are
BOOTPROTO=static
STARTMODE=onboot
IPADDR=192.168.0.2
NETMASK=255.255.255.0
Contents of file /etc/sysconfig/network/ifcfg-ens160 are
BOOTPROTO=static
STARTMODE=onboot
IPADDR=192.168.0.0
NETMASK=255.255.255.0
IPADDR_1=192.168.0.1
NETMASK_1=255.255.255.0
LABEL_1=ENS160:0
I restart the network by running systemctl restart network.service
and then run command /sbin/ipconfig -a, but I do not get both the IP address in results. I am not sure how to configure this.
You have filenames mixed up. If you use labels, you can just put everything into one file, namely the file which configures the main interface.
For example, put the following into /etc/sysconfig/network/ifcfg-ens160 to get interfaces ens160 and ens160:foo:
BOOTPROTO=static
STARTMODE=onboot
IPADDR=192.168.0.2
NETMASK=255.255.255.0
IPADDR_1=192.168.0.1
NETMASK_1=255.255.255.0
LABEL_1=foo
As a side note, this question should be in superuser or Unix & Linux Stack Exchange instead of SO as it's not a programming question.
Related
This seems to be a new issue with network-manager-openconect-gnome in Ubuntu 18.04+
I install sudo apt install network-manager-openconnect-gnome to get gnome integration with opeconnect and Cisco AnyConnect Compatible VPN (openconnect)
As an aside (which may actually be relevant) I do this to get *.local addresses to resolve:
sudo ln -sf /run/systemd/resolve/resolv.conf /etc/resolv.conf as per systemd docs
Move dns before mdns4_minimal in /etc/nsswitch.conf
If I connect to the VPN with openconnect through the gnome network manager, VPN addresses (sites for work) do not resolve. Regular sites continue to work as expected.
If I connect to the VPN with openconnect on the command line with sudo openconnect vpn.mycompany.com, VPN addresses (sites for work) do resolve. Regular sites continue to work as expected.
I thought I would check to see if there were any differences between /etc/resolv.conf with each of these VPN connection methods and sure enough, there is one:
openconnect on the command line (working):
##VPNC_GENERATED# -- this file is generated by vpnc
# and will be overwritten by vpnc
# as long as the above mark is intact
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 10.10.10.10
nameserver 10.10.10.11
search broadband mycompany.com
openconnect gnome integration (not working):
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 192.168.1.1
nameserver 10.10.10.10
nameserver 10.10.10.11
search broadband mycompany.com
If I remove (or comment out) the nameserver 192.168.1.1, which is the difference in content between the working and not working files... everything works as expected. I can resolve addresses within the company and regular sites work as expected.
This does not happen with Fedora. Everything works out of the box. I'm not sure why the network-manager-openconnect-gnome package works differently or if there's a way I can make it work without either
Editing the file by hand.
Using the openconnect tool from the command line and keeping a terminal open running that command.
Background
I have a command-line application that I use to connect to a remote device on port 1234. I cannot change the port number, and I do not have access to the source to rebuild this tool. I'm currently working in a lab where all ports except SSH are blocked. To get around this, I create a tunnel, i.e.:
ssh -L 1234:remotehost:1234 sshuser#remotehost
Now, I can just point my CLI program at localhost:1234 to connect with my CLI tool to the desired host.
Problem
This CLI tool needs to run for about an hour straight, and I have about 200 remote hosts to test with it. I would like to parallelize this task. Unfortunately, I can only create a single tunnel on my local machine using port 1234.
Question
Is there a (trivial/simple/automated) way to jail/sandbox my CLI tool so that I can launch 100 instances in parallel (i.e. via a shell script) so that each instance "thinks" it's talking to port 1234? For example, does Docker or KVM provide some sort of anonymous/on-demand compute node feature that I could setup rapidly? I'd rather not have to resort to manually deploying and managing a slew of VirtulBox hosts via vagrant.
The simple answer is that you can use multiple IP addresses locally. Each local IP address on the client will allow you to create another tunnel. Currently, you are using localhost. But your client also has an IP address. You can prove my point by trying this syntax:
ssh -f -N -L 127.0.0.1:1234:remotehost1:1234 sshuser#remotehost1 # this is default
ssh -f -N -L <local-IP1>:1234:remotehost2:1234 sshuser#remotehost2 # specifying non-default value <local-IP1>
Now, you just need to figure out how to give your client multiple IP addresses (secondary addresses). Then you can expand this beyond 2 parallel sessions.
I've also added -f and -N to your ssh syntax to put ssh into the background (-f) and to not issue any commands.
Using -R tunnels in the past, I've found that I need to enable GatewayPorts on the server (/etc/ssh/sshd_config). In the case of -L , I don't see the need. However, the ssh man-page explicitly mentioned GatewayPorts associated with the -L function. You may need to play around a bit. I just tried this out on my Mac and I was able to get it going without any GatewayPorts considerations.
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Working with Ubuntu 18.04 Server LTS. I am trying to find a way to check the DNS IP(s) that is actually being used when set via DHCP. The resolv.conf only will point to 127.0.0.53 now. /etc/systemd/network folder is empty. The NSLOOKUP output also always references the internal 127.0.0.53 IP. Seems all the old tricks aren't working.
The Ubuntu documentation is not updated yet as it still looks like the help for 16.04 referencing eth0, ifup and ifdown which are all deprecated on 18: https://help.ubuntu.com/lts/serverguide/network-configuration.html
I've tried setting a static adapter setup with Netplan via a custom .yaml. The settings work fine but I can't seem to find the DNS IP that I set anywhere. I expect it will be consistent between DHCP and static settings but I'm not sure where to look now.
I would settle for either a C library call or a bash CLI method at this point. Does anyone have a way to check this on 18.04 Server?
I found the following showed my the DNS servers by adapter towards the end of the output:
systemd-resolve --status
It contains a list under 'DNS Servers' organized by Link. I think this has changed from previous versions with Ubuntu. It will take a little text parsing work but this gives me what I'm after.
Another way is:
cat /run/systemd/resolve/resolv.conf
That file is dynamically generated by systemd-resolved, but contains the actual DNS servers instead of 127.0.0.53.
In fact, if you want make that the default for /etc/resolv.conf, you simply create symlink for it. (/etc/resolv.conf is a symlink that points to /run/systemd/resolve/stub-resolv.conf by default):
sudo mv /etc/resolv.conf /etc/resolv.conf.orig
sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
Sample /run/systemd/resolve/resolv.conf :
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 10.1.2.3
search host.domain.com
For more info:
http://manpages.ubuntu.com/manpages/bionic/man8/systemd-resolved.service.8.html
You can also use:
nmcli dev show eth0
Replace eth0 with your network interface to see how it was configured. If you got the DNS address over DHCP, you should see it here.
I'm running ubuntu 22.04.
sudo nmcli dev show <interface> didn't have any dns listings, but sudo resolvectl status <interface> showed me the current dns server.
I am suprised at this too. I am running Ubuntu 16.04 LTS and see something similar.
If you issue a
dig www.google.ca +trace | grep 'Received'
The first host in the response is the one doing the lookups for your server.
$ dig www.google.ca +trace | grep 'Received'
;; Received 525 bytes from 127.0.1.1#53(127.0.1.1) in 19 ms
;; Received 42 bytes from 199.7.91.13#53(d.root-servers.net) in 32 ms
This means that this box is doing it's own dns lookups directly to the root servers and following the path recursively to get my dns lookups.
Found the issue is that dnsmasq is enabled. To disable it do as follows.
edit the NetworkManager.conf file
sudo gedit /etc/NetworkManager/NetworkManager.conf
comment out the dnsmasq line
#dns=dnsmasq
restart the network-manager service
sudo /etc/init.d/network-manager restart
then verify that it is using the dns-server assigned via dhcp
$ dig www.google.ca +trace | grep 'Received'
;; Received 525 bytes from 192.168.30.1#53(192.168.30.1) in 18 ms
;; Received 42 bytes from 198.41.0.4#53(a.root-servers.net) in 32 ms
Ive got 4 dev VMs for four projects (all VMware Player VMs w/ubuntu 15.04 host) where each is running VNC (ports 5900, 5901, 5902, 5903) respectively.
I downloaded noVNC and saved to /var/www/html (my apache2 server on same host). Based on the ReadMe I then ran on my terminal
./utils/launch.sh --vnc localhost:5900
I received a missing websockify error, so downloaded it and placed it into the util folder. I then ran the same command and it worked! The terminal told me to Navigate to a url and sure enough I could control my VM.
However -- I'm wondering how can I use noVnc to access all 4 VM's? Is there some simple way to extend the port to a range like in iptables or firewalld?
./utils/launch.sh --vnc localhost:5900-5903
Okay, Ill answer for myself here in case it helps someone in the future...
First, create a token file where each line has a nickname, ip address, and port.
I created a file named token.list where each line looks like:
localhostnickname1: localhost:5900
localhostnickname2: localhost:5901
...
Then I use my terminal to go into the websockify folder so I can see the run file. I issue it the command:
./run --web /path/to/noVNC --target-config /path/to/token.list localhost:6080
Finally, I open my web browser and go to :
http://localhost:6080/vnc_auto.html?path=?token=localhostnickname1
Where localhost1 is the nickname of my first server on the first line of token.list
This link was my reference. If you want to serve this outside of localhost -- change the parameter localhost:8060 from localhost to an IP
Using a kickstart file that stops with a dialog "You have multiple
network devices on this system. Which one do you want to install through?"
The machine being configured with PXEboot has two Ethernet interfaces. What's
missing from the network entries below? I'd like this install to proceed
without asking which Ethernet interface.
PXE begins the install with DHCP, so Kickstart should already know which of
eth0, eth1, etc. to use.
Here is the Ethernet line in the ks.cfg file:
network --onboot yes --device eth0 --bootproto dhcp --noipv6
Any ideas appreciated.
NOTE: I have already tried the below option and it didn't work:
In pxelinux config file:
add ksdevice=bootif
also add "IPAPPEND 2" to the end of the file
In kickstart file, don't specify a device:
"network --bootproto dhcp"
How to force an kickstart installation to take place over a specific Ethernet device?
Maybe your network devices' names had been renamed, for example, em1, em2 ... in Dell servers.
In that case you can add biosdevname=0 to the kernel boot arguments, that will prevent biosdevname from being invoked.