Post funny things about programming here! (Or just rant about your favourite programming language.)
It happened to me when I was configuring IP geoblocking: Only whitelist IP ranges are allowed. That was fetched from a trusted URL. If the DNS provider just happened to not be on that list, the whitelist would become empty, blocking all IPs. Literally 100% proof firewall; not even a ping gets a pass.
That moment when you forget to run sudo ufw allow ssh after enabling the firewall
You mean before?
Not exactly the same thing, but on one of my systems, eth0 and eth1 swapped position after a kernel update, so the IP was on the wrong interface. I had IPMI/BMC on the system so didn't have to physically go to it and plug in a keyboard and monitor, but I still had to deal with manually typing a long randomly-generated password, twice (one to log in and once again for sudo).
I'm glad "predictable" interface names are supported now. Those eth0/eth1/etc names were dangerous since the numbers were just based on the order the kernel loaded the drivers and initialized them in, which can change across reboots. The predictable names are based on physical position in the system, so they're consistent across reboots.
it's become self aware and is always blocking ports 22 & 23.
This literally happened to me yesterday. Fortunately ufw enable did not configure it as persistent across reboots 🤠
UART it
Connects a monitor and a keyboard to the Raspberry Pi
Defeatedly Connects a monitor and a keyboard to the Raspberry Pi
@GolfNovemberUniform @treechicken so we deduct he has no Raspberry 400
I mean, yea? Why would they buy a 400 if it's unnecessarily more expensive?
It’s cute
What is a good firewall that can also block ports published with docker? I'd need it to run on the same host.
Are your Docker containers connecting to the network (eg using ipvlan or macvlan)? The default bridge network driver doesn't expose the container publicly unless you explicitly expose a port. If you don't expose a port, the Docker container is only accessible from the host, not from any other system on the network.
They are Only in my docker bridge networks and have a few published ports
If you don't want the Docker container to be accessible from other systems then just don't publish the port.
You want a virtual firewall. Is this for profit or just your science project because that's going to change the answer. You might hate me, but I'm still gonna say it, Cisco....
UFW does work with Docker, but requires some tweaking. IIRC you have to disallow Docker to modify IPTables and then add a rule to forward all traffic to the Docker network of your choice. It's a little finicky but works.
But…why?
Project Calico is designed for segmenting network traffic between kubernetes workloads.
Right tool for the job.
Also if you are a Fortinet shop, supposedly you can manage rules with FortiManager. I haven’t tried that yet but it looks really cool.
Interesting, I might have to read up on that next time. Thanks
Ufw should work, jus ufw block/limit/allow port number
I remember trying with ufw and the docker ports were still open. Iirc I've read somewhere that docker and ufw both use the same underlying software, so ufw cannot block docker (IP tables?)
Hmm, not sure. I know with docker you can "mock" ports for the container, where the port the container sees is different than the port on the system. Maybe you can do something with that?
this is me dealing with ZScaler at work
Happened to me in work once... I was connected via SSH to one of our test machines, so I could test connection disruption handling on a product we had installed.
I had a script that added iptables rules to block all ports for 30 seconds then unblock them. Of course I didn't add an exception for port 22, and I didn't run it with nohup, so when I ran the script it blocked the ports, which locked me out of SSH access, and the script stopped running when the SSH session ended so never unblocked the ports. I just sat there in awe of my stupidity.
Out of curiousity, how would nohup make your situation different? As I understand, nohup makes it possible to keep terminal applications running even when the terminal session has ended.
If the script was supposed to wait 30 secs and then unblock the ports, running with nohup would have allowed the ports to be unblocked 30 secs later. Instead, the script terminated when the SSH session died, and never executed the countdown nor unblock.
Thanks for the elaborate answer!
Any time! :)
the script stopped running when the SSH session ended so never unblocked the ports
the script stopped running when the SSH session ended
tmux
Always use tmux when possible for remote connections.
What does it do in this case?
Tmux essentially creates a pseudo-shell that persists between sessions.
So you can start a process, detach the session, start something else, disconnect, come back next week, and check on it.
It does other things too. Like console tiling.
Well, the script could keep running even after he would have detached from that tmux session due to losing ssh connection. And since that script would unblock all ports after 30 seconds...
(Same use case as nohup that they mentioned)
We've all experienced the walk of shame to the server room to hook up a monitor keyboard.
Ah, if only it was a server room and not a customer 3 hours drive away. And he'd closed and gone home for the night.
Fortunately it just needed a reboot, and I was able to talk him through that in the morning.
Oof I did a firmware upgrade on my main external firewall.
The upgrade went fine but when we added an ISP a month or so prior, I forgot to redistribute the ISPs routes. While all my ISPs were technically working, and the firewall came back up, nothing below it could get to the internet, so it was good as down.
Cue the 1.5 hour drive into the office…
Had that drive to think about what went wrong. Got into the main lobby, sat down, joined the wifi, and fixed it in 3 minutes.
Didn’t even get to my desk or the datacenter.
Oof... well you can just say "it must be some hardware problem or something... maybe a reboot will fix it."
lol. When I get asked what went wrong at work. So. A solar flare can swap the bits…