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ValdikSStoday at 1:22 AM2 repliesview on HN

>perf is a shell tool. iptables is a shell tool. sshguard is a log reader and ultimately you will use the CLI to take action.

Well yes, and to be honest in this case I did that all over SSH: run `perf`, generate flame graph, copy the .svg to the PC over SFTP, open it in the file viewer.

What I really wanted is a web interface which will just show me EVERYTHING it knows about the system in a form of charts, graphs, so I can just skim through it and check if everything allright visually, without using the shell and each individual command.

Take a look at Netflix presentation, especially on their web interface screenshots: https://archives.kernel-recipes.org/wp-content/uploads/2025/...

>look into nft - iptables is sooo last decade

It doesn't matter in this context: iptables is using new netfilter (I'm not using iptables-legacy), and this exact scenario is 100% possible with native netfilter nft.

>Finally, 13,000 address in an ipset is nothing particularly special these days

Oh, the other day I had just 70 `iptables -m set --match-set` rules, and did you know how apparently inefficient source/destination address hashing algorithm for the set match is?! It was debugged with perf as well, but I wish I just had it as a dashboard picture from the start.

I'm talking about ~4Gbit/s sudden limitation on a 10Gbit link.


Replies

gerdesjtoday at 2:04 AM

"What I really wanted is a web interface which will just show me EVERYTHING it knows about the system in a form of charts, graphs, so I can just skim through it and check if everything allright visually, without using the shell and each individual command."

Yes, we all want that. I've been running monitoring systems for over 30 years and it is quite a tricky thing to get right. .1.3.1.4.1.33230 is my company enterprise number, which I registered a while back.

The thing is that even though we are now in 2026, monitoring is still a hard problem. There are, however, lots of tools - way more than we had in the day but just like a saw can rip your finger off instead of cutting a piece of wood, well I'm sure you can fill in the blanks.

Back in the day we had a thing called Ethereal which was OK and nearly got buried. However you needed some impressive hardware to use it. Wireshark is a modern marvel and we all have decent hardware. SNMP is still relevant too.

Although we have stonking hardware these days, you do also have to be aware of the effects of "watching". All those stats have to be gathered and stashed somewhere and be analysed etc. That requires some effort from the system that you are trying to watch. That's why things like snmp and RRD were invented.

Anyway, it is 2026 and IT is still properly hard (as it damn well should be)!

gerdesjtoday at 1:45 AM

>Oh, the other day I had just 70 `iptables -m set --match-set` rules, and did you know how apparently inefficient source/destination address hashing algorithm for the set match is?! It was debugged with perf as well!

>I'm talking about ~4Gbit/s sudden limitation on a 10Gbit link.

I think you need to look into things if 70 IPs in a table are causing issues, such that a 10Gb link ends up at four Gb/s. I presume that if you remove the ipset, that 10Gb/s is restored?

Testing throughput and latency is also quite a challenge - how do you do it?