endlessh was pretty cool and a more modern version is even better ! I’ll give it a shot !

On a side note, I found a way to trap HTTP connections too while working on my cyb.farm project. The go implementation is ridiculously simple: tarpit.go. It works by providing an endless stream of custom headers to the client, which it is supposed to ingest before getting to the content itself.

Keeping the source IP intact means you’ll have troubles routing back the traffic through host B.

Basically host A won’t be able to access the internet without going through B, which could not be what you want.

Here’s how it works:

On host A:

• add a /32 route to host B public IP through your local ISP gateway (eg. 192.168.1.1)
• setup a wireguard tunnel between A and B
• host A: 172.17.0.1/30
• host B: 172.17.0.2/30
• add a default route to host B wireguard IP

On host B:

• setup wireguard (same config)
• add PAT rules to the firewall so to DNAT incoming requests on the ports you need to 172.17.0.1
• add an SNAT masquerade rule so all outbound request from 172.17.0.1 are NATed with host B public address.

This should do what you need. However, if I may comment it out, I’d say you should give up on carrying the source IP address down to host A. This setup I described is clunky and can fail in many ways. Also I can see no benefits of doing that besides having “pretty logs” on host A. If you really need good logs, I’d suggest setting up a good reverse proxy on host B and forwarding it’s logs to a collector on host A.

OpenBSD is the most pleasing expérience I’ve had with an OS. It’s fully contained and has all the tools you need without needing to install anything (eg a DNS, HTTP, SMTP servers, a proxy, a good firewall). All config files look alike and use the same keywords for the same things, making it straightforward to configure everything.

And regarding RAID 1, I’ve never done it myself, but it totally works out of the box (as well as full disk encryption).

OpenBSD for all of them.

A VPN is easy to setup (and I have it setup by the way), but no VPN is even easier. SSH by itself is sufficiently secure if you keep it up to date with a sane configuration. Bots poking at my ssh port is not something that bother me at all, and not part of any attack vector I want to be secure against.

Out of all the services I expose to the clear web, SSH is probably the one I trust the most.

Yeah I know, I just don’t really care about that traffic to bother changing it :) Also, I’m talking about a server hosted on Hetzner, so I feel like it’s scanned a lot.

I get what you say, and you’re definitely not wrong to do it. But as I see it, you only saved ~80Kib of ingress and a few lines of logs in the end. From my monitoring I get ~5000 failed auth per day, which account for less than 1Mbps average bandwidth for the day.

It’s not like it’s consuming my 1Gbps bandwidth or threatening me as I enforce ssh key login. I like to keep things simple, and ssh on port 22 over internet makes it easy to access my boxes from anywhere.

Congratulations! A mail server is quite demanding in terms of initial setup, but it’s also very rewarding !

Here are a few pointers I can give you:

• Using a good domain is important, some provider block entire TLDs for cheap domains (eg. .tk or .pw). I learnt it the hard way…
• Set your MX records to A records, not CNAME
• Ensure your PTR records match your A records for the mail server
• Learn about SPF and DKIM
• Set them up, and verify with mxtoolbox
• Use the ip4:<ipv4> and/or ip6:<ipv6> selectors for SPF
• Setup a spamfilter (I like spamassassin)
• Leave it all running for a few weeks/months
• Publish a DMARC policy on your DNS, and verify with mxtoolbox

This should limit a lot your likeliness to end up in spam folders (which is usually the hardest part about running your mail server)

ELI5

So it’s saturday afternoon, a very hot one, so you ask your daddy for an ice cream (hosted service). The shop you go in is very bizarre though, as there is one vendor (TCP port) for each flavor (docker service/virtualhost). But it’s tricky because they’re all roaming in the shop, and you don’t know who’s responsible for each flavor. Your dad is also not very comfortable paying these vendors directly because they only accept cash and do not provide any receipt (self-signed certificate/no TLS).

Hopefully, there is the manager (reverseproxy) ! This girl is right where you expect her: behind the counter (port 80/443), accept credit cards and has a receipt machine (Domain name + associated certificate). She also knows everyone on her team, and who’s responsible for each flavor !

So you and your dad come to see the nice lady, ask for a strawberry + chocolate ice cream, and pay her directly. Once done, she forwards your request directly to the vendors responsible for each flavor, and give you back your ice cream + receipt. Life is good, and tasty !