Kid_Thunder

Sounds like you have nothing listening on port 80 that resolves for your domain for Let’sEncrypt to verify that you own the domain. You need a webserver listening on port 80 and that Certbot can access if you’re using the http method.

Basically you’re forwarding traffic to port 80 but there’s nothing on port 80.

Depends on if there’s an IPv6NAT and how your ISP converts between IPv4 and IPv6 or actually supports IPv6 straight through. It also depends on your router.

Currently, there’s still some debate since IPv6NAT (NAT66/NPT6/NATv6) isn’t really needed for WAN boundaries for the reasons NAT exists. However, without it you are right on that this will be a problem for the consumer because PCs, IoT devices, printers, circuts or whatever my wife has, etc. could all be exploitable and even worse, you may never know you’re contributing to the botnet.

As an example, I have a global IPv6 on a few on my devices. They can connect to IPv6 if it originates from me but if it originates from them or is UDP it doesn’t route to my IPv6. My router doesn’t care. It’ll route it just fine either way. It would appear that my ISP has me behind one of the IPv6 NATs.

I’d imagine that’s true for most people at home.

NAT provides some measure of security as pure coincidence to how it works. It is not designed or intended to provide security. It does not inspect packet payloads in order to filter them for security. It looks at the header and attempts to route it to an internal IP address (your devices on your LAN) and if it cannot, it will drop the packet because the header will only have the external IP address – the packet has no idea which device it is supposed to go to. Forwarding a port is telling the NAT to assume that when a packet hits a certain port, if it doesn’t know the destination internal IP, forward it to some internal IP anyway.

The reason you can connect to websites, ssh outside, FTP, whatever, is because your connection comes from your internal IP first to some other IP and therefore, NAT knows which internal IP to route those packets to.

Take for example this scenario:

You download some software. It has malware that provides command and control (C2) to someone else outside of your network. A firewall and/or antivirus may be able to stop this and hopefully notify you. NAT will not help here. Furthermore, if you have uPNP enabled (usually it is by default on your router) the malware can forward any ports through your NAT to the compromised device opening it up to bot attacks and the like.

Another scenario:

You want to play a video game with you and your friends and you’re going to host it. So either you manually forward those ports or perhaps uPNP just does it for you. That game has an exploit known by attackers, or perhaps it can just be DDoS’d. Your NAT isn’t going to stop that. Hopefully a firewall will help you here. It definitely will if you set up explicit rules so that if they aren’t your friend’s IPs it will drop them. Though it is possible the game is exploitable and your friend’s are compromised.

Take for example malware has been known to spread via Minecraft.

As I understand it, NAT is a firewall

NAT is not a firewall. NAT does not inspect packet payloads, it doesn’t do anything except attempt to route packets to where they are supposed to go. If the connection originates from outside or it is a ‘connectionless’ protocol, the NAT has no idea which internal IP to route to, so it drops the packet.

NAT provides some security by sheer coincidence and not by design.

The SSH keys don’t help me if I get locked out of a Domain Controller unless you’re using OpenSSH (which is now a native feature you can turn on). In that case you can actually still log into the DC via command line because it authenticates based on authorized_keys and not the LDAP of the DC. I actually do this on the enterprise, not because I may get locked out but because it is just convenient. Granted you’ll have to execute powershell on the command line once in to use the AD cmdlets.

On the other hand when you create a DC now-a-days (Server 2019…I don’t remember if this is asked in the wizard when in Server 2016) you can create a “Directory Services Restore Mode” password which is basically a local admin account on the DC that you can log into only when the DC is booted into safe mode. You’ll be asked to create it when you promote your DC.

Personally I use FreeIPA for my LDAP. I like that I can create sudoers rules from one centralized place and manage ssh keys across all clients. Granted I could just use Ansible I suppose, which is how I update multiple distributions in my network and online but I like that I can just change SSH keys and sudoers from one place easily instead of changing tasks/roles. I also usually run cockpit even on my non-Red Hat distros with SSH keys just so I don’t have to log into everything though it is somewhat limited outside of the Red Hat sphere.

If you don’t want to use ProxMox or some other specialized HyperVisor ecosystem, you can also use Cockpit to manager your VMs along with your Pods. I wish there’d be more attention to it for features because it feels like it could do a lot more.

I also don’t really worry about locking myself out for two reasons:

1. I use SSH keys.

2. I also have a break-glass local account on every system…with SSH keys. If its on your local network, you can use VNC/VM console/Remote Desktop with a local account while only allowing SSH with keys if you’d like. Just make sure if you’re going to allow remote access outside of your network that you never forward the VNC/RDP ports. For SSH when I do this I always pick some random port – never default and never common ones like 2222 to at least keep my logs less noisy from the botnet auto attacks.

For my online VPS’ I use a firewall with geoIP from Maxmind and drop all ports but 443 from the world, except for whatever country I’m in. I drop all packets from certain countries that seem to auto-attack more often than others. I try to drop packets from all known (to me) Shodan scanners. If I’m not traveling I just restrict all other ports to my public IP’s subnet though my IP hasn’t changed for years. For status checking services like StatusCake, I use the “push” method instead using a simple cron job with curl instead of relying on servers around the world checking my ports. In this case, the services just check that my server has successfully hit them within X minutes to be “up”.

The free solution I was referring to was my comment about using ControlD, which certainly offers a free service…which is the comment that the other person was responding to.

I run pihole and my wireguard VPN server locks all queries through it, which in turn uses unbound and queries via different providers like Cisco’s OpenDNS, Cloudflare and Quad9. However, I wanted to present a similar offering that also has a free-tier without a query cap for people interested.

NextDNS caps your queries per month on the free account. ControlD doesn’t and you can pick a various mix of their public DNS resolvers. You don’t necessarily get the granular control with doing it this way for free that you can get with NextDNS though.

If you do check out these, make sure you click the Secure Resolvers if you’d prefer for DLS/DOQ/DNS over HTTPS instead of Legacy.

It does a DoD multi-pass shred by default

Just a heads up that’s not a thing anymore (since 2006 when the 1995 revision was superseded), except that you have to physically destroy it or whatever the CSA’s policy that owns it says to do. Generally the direction for an HDD would be, if available, use a degaussing rod and then regardless, you must shred it in an approved HDD shredder (a physical shredder) or incinerate it. For an SSD, it would be to incinerate it.

Now 5220.22-M (the 1995 version) that most commercial and some not-so-commercial software referenced as the “DOD Standard” doesn’t even exist anymore. It is now 32 CFR Part 117 of Title 32 and with respect to sanitization is §117.18 (b)(2).