nmcli | OBSOLETE NetworkManager command line interface

I have a CentOS 7 server which was running happily for 600+ days until it was rebooted recently, after which incoming web requests were receiving HTTP523 (Origin Is Unreachable) error codes (via Cloudflare, if that makes a difference?) unless I stopped the firewalld service. Things run fine without firewalld, but I'd rather not leave it disabled!

I've tried stopping docker and firewalld and restarting them in various sequences, but the same 523 error occurs unless I stop firewalld.

/var/log/firewalld contains a few warnings that might help:

• WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w10 -D FORWARD -i br-8acb606a3b50 -o br-8acb606a3b50 -j DROP' failed: iptables: Bad rule (does a matching rule exist in that chain?).
• WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w10 -D FORWARD -i docker0 -o docker0 -j DROP' failed: iptables: Bad rule (does a matching rule exist in that chain?).
• WARNING: AllowZoneDrifting is enabled. This is considered a n insecure configuration option. It will be removed in a future release. Please consider disabling it now.
• WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w10 -t nat -D PREROUTING -m addrtype --dst-type LOCAL -j DOCKER' failed: iptables v1.4.21: Couldn't load target 'DOCKER':No such file or directory
• WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w10 -t nat -D PREROUTING' failed: iptables: Bad rule (does a matching rule exist in that chain?).
• WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w10 -t nat -D OUTPUT' failed: iptables: Bad rule (does a matching rule exist in that chain?)
• WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w10 -t nat -F DOCKER' failed: iptables: No chain/target/match by that name.

I've found seemingly conflicting advice around the place regarding any manual configuration/commands required:

1. firewall-cmd --permanent --zone=trusted --add-interface=docker0 on a CentOS forum
2. firewall-cmd --zone=trusted --remove-interface=docker0 --permanent on the offical Docker docs -- surely that's the opposite of the above?
3. a bunch of manual firewall-cmd commands on a Docker github issue -- surely all of that isn't required?
4. this one looks promising -- nmcli, NetworkManager and firewall-cmd --permanent --zone=trusted --change-interface=docker0

I don't fully understand where the br-8acb606a3b50 interface comes from, or whether I need to do anything to configure it as well as docker0 if I use a solution like 4. above? It was all working fine automatically for years until the reboot!

Are some magic firewalld incantations now required (and why?!) or is there some way I can get the system to get back into the correct auto/default configuration it was in prior to rebooting?

I did something to mess up my DNS on my virtual ubuntu 16.04 box. Can you help me diagnose what the problem is and get DNS working again. I am able to connect to servers using an ip address. However, when I use hostnames, my box can't resolve them. This used to work - I did something to mess it up, but don't remember what file I edited.

ubuntu version:

I am on Fedora v33 Server edition (no GUI) and I have setup 2 network connections. One is Ethernet, which I use to connect my Macbook to the Linux machine, the other is the WLAN connection the machine uses to connect to the internet.

So now whenever I do

nmcli con up eno1

I lose access to the Internet (ping www.google.com does not return any packets)

When the ethernet is down everything works, but I cannot use ethernet obviously.

Something similar can happen on a Mac OS where I can simply "drag" a network to set the priority. How do I do the same using only the terminal on a unix system like Fedora?

I have a 100 Jetpacks that I have to sign in to configure. I am trying to do it in a bash script but I am having no luck. I can connect to the wifi no problem but my POST request are not achieving anything. Any Advice? Here is link to my github. I have copies of what I captured on Burp suite https://github.com/Jdelgado89/post_Script

TYIA

I am working with nmcli to create a modem connection using a SIM.

I need to know: is there a command (possibily, a nmcli command) that queries the SIM and returns an answer that tells whether the PIN is enabled or not on that SIM?

Thanks in advance.

When I’m in public I want to have access to the internet, so I’ve been writing a script to find wifi passwords for a while now. I found a way like “dictionary attack” that I don’t like. I found a script on the internet to connect to wifi using python:

I need to configure the [TRM240 modem][1] to work with a Raspbian system. I followed the procedure reported in the answer [here][2], but the connection isn't working.

I attach some screenshots documenting the procedure and the commands that I issued.

First, look for connected modems:

Consider the following command, which I am trying to execute on Red Hat Enterprise Linux 8 system.

nmcli con add help | less

Some of the help pages for specific COMMANDs are quite lengthy and piping to less is not working as I would expect. Normally a command like 'man nmcli | less' provides the first page and you have to use navigation to get to the bottom. In this case it shows me the last page, and I can't page up. Attempting to do so results in a page full of blank lines. I'd like to see all of the help documentation for that particular combination of the object and add command. For some reason the help option for the nmcli command is not working well with the less utility. If I try to use '>' to redirect to a file I end up with a blank file.

Resolving an external domain from within a pod fails with SERVFAIL message. In the logs, i/o timeout error is mentioned.

External domains should be successfully resolved from the pods.