Show HN: Network Monitor – a GUI to spot anomalous connections on your Linux

A real-time network connection monitoring tool built with Rust and GTK4, displaying active connections with live I/O statistics in a modern graphical interface. https://github.com/grigio/network-monitor

155 points

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grigio

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7 days ago

57 comments

heybrendan ・ 2 days ago

I see that you're parsing `ss` output in 'src/services/network.rs' (L22-L31) [1]. I find this to be a rather shaky foundation as any future drift or deviation in the `ss` utility's output could potentially yield unforeseen consequences.

I'm vaguely aware that there are crates available in the Rust ecosystem for interrogating and manipulating sockets much more directly as well as high level abstractions for all things netlink (read: AF_NETLINK). Is wielding Rust's socket/netlink libraries unsuitable in some way, or was it merely deemed out of the design scope?

Very cool project, please keep going!

[1] https://github.com/grigio/network-monitor/blob/master/src/se...

jrm4 ・ 2 days ago

Fantastic, more of this. I don't know if I'm just missing it or what, but I'd love a GUI thing that showed all the devices on my network maybe even with a graph view.

I'm using an Eero router out of laziness and even it has some features here that I'd like to see more of in polished "home-user" style network tools; especially since it seems as if more are getting into the "homelab"/"selfhosted" thing.

  • bongodongobob ・ 2 days ago

    That's impossible to do reliably without using agents, SNMP, or some other kind of communication protocol that you'll have to set up on each device. If you're ok with that, use SNMP. If you want topology, you'll have to have an agent that logs into all your networking gear and parses the configs.

    • jrm4 ・ a day ago

      "Reliably" is doing a lot of heavy lifting; I'm aware that with a combination of all the netstats and pings and nmaps there are ways to poke around.

mordechai9000 ・ 2 days ago

Nice work!

I do want to say, I don't like having to rely on scraping ss output. But that's not a comment on this project - I have done the exact same thing. It just proved to be the most expedient way given the constraints I was under. I suspect there is a lot of devops and CI/CD code out there that relies on the output format of ss. My concern is that parsing text intended for human readability and not machine processing is brittle and prone to failure due to unforeseen circumstances, or a package upgrade that changes the behavior.

  • mbana ・ 2 days ago

    I was going to say the same thing.

    I really like the eBPF approach as pointed out to by the other comments. I feel like this is the ideal approach, please correct me if I'm wrong.

    A callback based approach as opposed to (constantly) polling the output of some command is ideal.

BoppreH ・ 2 days ago

Cool project, I wish we had more GUIs for these OS functions. How was your experience with GTK4 and Rust?

And it's a bit sad that in the year of our lord 2025, the best way to get such fundamental information is by using regexes to parse a table[1], generated by a 6000-line C program[2], which is verified by (I hope I'm wrong!) a tiny test suite[3]. OSQuery[4] is also pretty cool, but it builds upon this fragile stack.

That's something I miss from Windows, at least PowerShell has built-in commands that give you structured output.

[1] https://github.com/grigio/network-monitor/blob/9dc470553bfdd...

[2] https://github.com/iproute2/iproute2/blob/main/misc/ss.c

[3] https://github.com/iproute2/iproute2/blob/main/testsuite/tes...

[4] https://osquery.io/

  • rickydroll ・ a day ago

    > And it's a bit sad that in the year of our lord 2025, the best way to get such fundamental information is by using regexes to parse a table[1],

    Look at nutshell an see if that gives you what you are looking for https://www.nushell.sh/

  • typpilol ・ 2 days ago

    I am in the process of building myself a cross platform GUI for network monitoring.

    Simply because I need one for non-critical stuff and things like uptime robot are enterprise geared and too expensive for me to entertain.

    I wish there was an uptime robot for like 25 cents a monitor a month.

  • simoncion ・ 2 days ago

    > It's a bit sad that [we're parsing output] ... generated by a 6000-line C program[2] ...

    > That's something I miss from Windows, at least PowerShell has built-in commands that give you structured output.

    It sure is something to disparagingly point to the LoC of 'ss' in one sentence, then pine for both PowerShell and the Windows infrastructure that supports it in the next.

    You mentioned processing the output with regexes. That's definitely a code smell, but this is one line of the data from the 'ss' command in question, with fancily-aligned header line included, but with vast tracts of whitespace removed. The regex you pointed out is processing the column whose comma-separated data is enclosed in parens:

      Netid State     Recv-Q Send-Q  Local Address:Port  Peer Address:Port Process                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
  tcp   LISTEN    0      666              [::]:22            [::]:*     users:(("sshd",pid=1337,fd=7)) ino:1338 sk:2024 cgroup:/openrc.sshd v6only:1 <->
    They definitely didn't have to use a regex to process that, but chose to.

    You could argue that a system that let you write client code that goes something like

        socket[i].process.users[0].cmd, socket[i].process.users[0].pid, socket[i].process.users[0].fd
    is superior to one that requires writing something that makes use of the moral equivalent of 'cut'. I'd argue two things, one of them informed by my professional experience with PowerShell

    1) What happens when the "structured" data you rely on changes shape? When that system that produces that "structured" data changes 'users' to 'user_list', 'cmd' to 'local_command', or deletes 'process' and moves 'users' up into its place, you're just as screwed as if 'ss' changed its output format in a way that wasn't backwards-compatible.

    2) The core Microsoft tools might all produce "structured" data, but -in my professional experience- so, very, very little "community-provided" PowerShell code does. Why? I don't know for sure, but probably because it's notably more difficult to make a script or library produce that sort of data than it is to just emit regularly-formatted text.

    • BoppreH ・ 2 days ago

      The problem of data changing shape can happen regardless, but with text you have the added danger of escaping characters and ambiguities. Not to mention there are ad-hoc text formats for each and every tool, which can change from one version to another.

      And you're right, PowerShell is far from perfect. I miss some of its design goals, not the whole thing.

mroche ・ 2 days ago

Cool project! As a more advanced form, I think it should be possible to get all this information via eBPF rather than ss output and scraping /proc.

Food for thought!

  • oneshtein ・ 2 days ago

    eBPF doesn't work on locked down kernels (stock kernels in Secure Boot mode).

    • mroche ・ 2 days ago

      eBPF is restricted when booted in a SB environment, but it's not nonfunctional. The default config puts the kernel into "integrity" mode of Kernel Lockdown, which reduces scope of access and enforces read-only usage.

      Whether or not the specific functions needed to replicate this tool are impacted is beyond my knowledge.

    • grigio ・ a day ago

      I think this is a great point, eBPF is cool but probably less popular than ss

neilv ・ 2 days ago

Thanks especially for using GTK with Rust to do this. We need to keep desktop Linux GUI libraries alive and viable (as an alterative to Web site GUI frameworks, Electron apps with Web frameworks, and proprietary mobile app platforms).

  • hombre_fatal ・ 2 days ago

    Though I was let down last week when I ported a TUI to GTK4 and found out that even a hello world gtk4.h C app uses 200mb RAM.

    I haven’t tried it yet but I believe Qt will weigh around the same.

    The TUI I ported uses <8mb RAM so I kinda lost interest in the GUI endeavor for my tools since I like to have one running in each project workspace.

    • exploraz ・ 2 days ago

      > Though I was let down last week when I ported a TUI to GTK4 and found out that even a hello world gtk4.h C app uses 200mb RAM.

      Bit of a rant I wanted to share here:

      I've seen the same happened on zenity (a GUI dialog utility for shell scripts) since they migrated from GTK3 into GTK4.

      Now zenity took almost 2 seconds to launch instead of .5 to a second when they still used GTK3.

      This might be an issue on both libadwaita and GTK4 itself.

      Both pavucontrol (which uses GTK4 but not libadwaita, at least for now) and even a simple dialog in zenity (GTK4+libadwaita) consumed over 100 MiB of memory according to btop measurement, while both thunar and engrampa, which is both GTK3 apps, only consumed half the amount of memory usage (about 50 MiB according to btop).

      However, I've noticed that zenity, GNOME apps, and other apps that uses libadwaita took longer to launch compared to apps that only used GTK4 (pavucontrol), which launched as fast as other GTK3 apps does.

      • hombre_fatal ・ a day ago

        Hmm, maybe looking at btop memory usage is too naive.

        I'm not very knowledgeable here, but apparently that includes the memory of libraries that other gtk4 apps would share.

        If I launch 5x instances of my app and look at /proc/<pid>/smaps:

            | PID    | Private | PSS      |
    |--------|---------|----------|
    | 360955 | 65.4 MB | 133.0 MB |
    | 360956 | 52.1 MB | 105.0 MB |
    | 404303 | 65.8 MB | 132.9 MB |
    | 404304 | 65.8 MB | 133.2 MB |
    | 404305 | 65.9 MB | 132.6 MB |
        Looks like PSS includes private memory + shared libraries divided by the processes using them, so a little better than the 200mb that btop shows, but still over 2x heavier than, say, a hello world on macOS.
      • exploraz ・ 2 days ago

        Update: It turns out that in GTK4, half of the memory usage were dedicated to OpenGL hardware rendering alone.

        Using GSK_RENDERER=cairo almost halved the memory usage of most GTK4 apps, but it doesn't fix the startup time.

SlavikCA ・ 2 days ago

That screenshot / video on README page is mostly unreadable. Can't get anything out of it.

  • IshKebab ・ 2 days ago

    This app is clearly a demonstration of GTK4's light/dark transition animation. Looks like it works perfectly to me!

  • voodooEntity ・ 2 days ago

    Same for me.

    What info does it show more than a:

    "netstat -tulpn"

    Wrote myself a script years ago that basically loops netstat -tulpn watch like for the same purpose - just wondering if your tool shows me more than that.

    • Simon-curtis ・ 2 days ago

      modern graphical interface, for a start

      • voodooEntity ・ 2 days ago

        I was asking which information it shows not what output it uses to display that information....

  • hamburglar ・ 2 days ago

    Come on, now. You can see that it supports today’s most critical feature: it has dark mode and light mode.

    /s

    • noir_lord ・ 2 days ago

      If you live in the terminal it's all dark mode*

      * unless you are one of those weirdo's who has a black on white terminal in which case you should be on a watch list (/s in case wasn't immediately obvious).

      • bolangi ・ 2 days ago

        I've been there since the DOS days when it was all dark mode, green phosphor characters on a black CRT. I was there when amber monitors were the new thing. (I still love sunglasses with brown lenses.) And I watched the early Apple computers with graphics and black-characters-on-white display style that has been the rage ever since... well since the recent new thing being dark mode.

        It reminds me of fashion trends, miniskirts then maxis, up and down past the knee like tides.

        Fads, that's the word.

      • hamburglar ・ 2 days ago

        I am exactly that kind of weirdo, but then again I’ve been reading black on white books for my entire life and I never thought to complain about it.

butz ・ a day ago

First, a praise: Thank you for using native desktop UI, not some web framework and shipping additional browser along. And a bit of critique: Main screenshot should be bigger, and present the main view of the application. Ability to switch light/dark mode comes by default and target audience is more likely to see what data application displays and how.

  • grigio ・ a day ago

    Welcome, yes i put a better screenshot

cookiengineer ・ 2 days ago

This shows only the contents of /proc fs, right?

If you want realtime connection details, eBPF and XDP allow much more insights for that, as you can also parse network protocol payloads and implement adapters for each network protocol.

WD-42 ・ 2 days ago

Nice work. I’ve been writing an app using the same stack. The gtk-rs bindings are actually pretty productive once you get used to it! And it’s so fast.

lone-cloud ・ 2 days ago

The code is partly refined AI generated slop and the UX is lacking. The functionality is very basic and needs to be more thoroughly tested. This type of project is half a work day tops for a senior+ dev to create with agentic coding.

  • johannesrexx ・ 2 days ago

    May I ask how you made the determination that network-monitor is "partly refined AI generated slop"?

    • lone-cloud ・ 2 days ago

      The mindless code comments are a dead giveaway. It's always the same pattern of: "a thing" <--- here is a thing Generally a dev would clean these up, but when they don't it's a major red flag to me that it's just unreviewed vibe coded slop.

    • LoganDark ・ 2 days ago

      I came to this conclusion as well. The README gives off some vibes but the sheer volume and writing style of the code comments is what really sells it for me. For example:

      https://github.com/grigio/network-monitor/blob/9dc470553bfdd...

          // Enhanced styling with column-specific classes and alignment
      This sort of marketing-speak isn't what people typically put in their code, LLMs love buzzwords. It's not just this, it's everything, but hopefully you get what I mean.
Beijinger ・ 2 days ago

On a first look: The same as the shell tool nethogs, just with a GUI

XiS ・ 2 days ago

So nethogs, but with a gui?

kazishariar ・ 2 days ago

Submitted a pull request for MacOS Support - please approve. Tnx!