6 ms·

Tcpdump101 – Build packet capture syntax online

142 points by megahz 8y ago

j0057 8y ago
It would be more didactically useful to not use a lower-uppercase font for the resulting options, right now it causes a lot of confusion: should you use `-I eth0` or `-i eth0`? (I had to look it up, the lower case variant is the correct one.)
raister 8y ago
man tcpdump RTFM...
- larkeith 8y ago
  Because everyone knows GUIs provide no increase in usability and efficiency, especially to those who use the tool infrequently. How's HN looking for you in Lynx?
  - gerdesj 8y ago
    Its white on black and runs even faster.
    - raister 8y ago
      I get downvoted a lot, however, do we really need a tool to access another tool? I guess we don't - it is a pointless tool. If tcpdump is THAT important to you, it merits taking a deep look into the manual. Now, just because someone implemented a website with directions to a tool, it doesn't automatically translate to something useful.
      - danmg 8y ago
        Trying to make useful tools is hard. But, in this instance I think zsh does a better job... https://i.imgur.com/xeULphF.png https://i.imgur.com/xeULphF.png
      - philamonster 8y ago
        I kind of agree with both sides of this argument but the one thing I often find lacking in man is context, which I know not really the point. But there is in the layout of the commands in this tool a better path to understanding the switches one might need to accomplish whatever task is at hand. Personally, I've spent far more time grep'ing my history than using man. And true story, someone may have heard of at one point tcpdump or whatever but not know what man is. There's also people that transcend the platform multiverse that may spend hours, days or weeks building a bash script using linux tools that's used briefly or automated and will require familiarization if that process is ever reviewed/needed again. Tools like this and the regex visualization sites mentioned previously are great for that.
      - gerdesj 8y ago
        To be fair mate: you are spot on. I'll never use it and I'll still be reading the man page and the HTML howtos for a few years to come. That said, someone had a bash and put a spotlight on something. I have lost count of the times I have had to tell people to stop relying on "magic" and get a bloody packet capture out. Oh ... and log files.
      - isostatic 8y ago
        tcpdump is massively useful, I use it on a frequent basis with "-nn -T rtp", and some perl, to analyze missing/out of order RTP packets
  - danmg 8y ago
    Looks like this https://i.imgur.com/GO4lqRE.png https://i.imgur.com/GO4lqRE.png
moreira 8y ago
This is incredible and makes me think a website like this could and should exist, containing an interface to as many unix tools as possible. Yes, one could "RTFM" as one commenter mentioned, but if you're just a casual CLI user, this sort of interface seems incredibly handy. "I know I want to use cURL but I don't know what arguments I need to do X and Y". Use the interface to piece together a whole command, with nice instructions for every little flag and argument available so you know what you're doing. It's kind of like those visual regex builders. They're amazing!
- raister 8y ago
  and then, the next software version will change that -x by -X and all go to the fan.......
  - larkeith 8y ago
    For new tools and commands, sure, but most notable Linux utilities are mature and stable, with very few syntactic changes - so many production scripts already rely on syntax remaining static that changing it would break far more than the suggested tool.
    - stefan_ 8y ago
      You would think that. Then, oops, we're running dash, not bash. Or that sinking feeling you get when you think "that command line switch worked last week" on some "mature and stable" Linux utility only to realize that you're no longer running bash with real utilities, but ash with toybox or busybox builtins because some dickhead wanted to save 5 MiB on his docker image.
- zorpner 8y ago
  A/UX had a tool like this called Commando (you can see it in the third screenshot on this page: http://toastytech.com/guis/aux3.html http://toastytech.com/guis/aux3.html ).
  - 8y ago
john37386 8y ago
Cool stuff, I would personally enforce the "count" packet to 100 or 1000 by default. This way, you make sure that no one crashes this powerful device. If someone knows what is doing, then he could just disable it. Sniffing at +10Gbps can be tricky sometimes.
mimsee 8y ago
I'd like to see the source published on github with an Open Source license so I could fix a lot of the UX issues with this page.
- orf 8y ago
  https://tcpdump101.com/js/t101.js https://tcpdump101.com/js/t101.js 9,000 lines of Javascript, looking pretty handmade and very heavily coupled. I'm not sure if you'd make much progress.
  - londons_explore 8y ago
    But on the plus side, at least it isn't gobbling a gig of ram and lagging while react re-renders everything 25 times.
    - orf 8y ago
      And on the downside, it's an unmaintainable mess that would require a rewrite to have any hope of having a usable UI.
myrandomcomment 8y ago
So my first thought was this is really cool, and it is. However I realized I would never use it as if I need tcpdump, I am on a CLI and I am just going to type man for things I need to look up.

142 points by megahz 8y ago

It would be more didactically useful to not use a lower-uppercase font for the resulting options, right now it causes a lot of confusion: should you use `-I eth0` or `-i eth0`? (I had to look it up, the lower case variant is the correct one.)

raister 8y ago

man tcpdump RTFM...

larkeith 8y ago
Because everyone knows GUIs provide no increase in usability and efficiency, especially to those who use the tool infrequently. How's HN looking for you in Lynx?
- gerdesj 8y ago
  Its white on black and runs even faster.
  - raister 8y ago
    I get downvoted a lot, however, do we really need a tool to access another tool? I guess we don't - it is a pointless tool. If tcpdump is THAT important to you, it merits taking a deep look into the manual. Now, just because someone implemented a website with directions to a tool, it doesn't automatically translate to something useful.
    - danmg 8y ago
      Trying to make useful tools is hard. But, in this instance I think zsh does a better job... https://i.imgur.com/xeULphF.png https://i.imgur.com/xeULphF.png
    - philamonster 8y ago
      I kind of agree with both sides of this argument but the one thing I often find lacking in man is context, which I know not really the point. But there is in the layout of the commands in this tool a better path to understanding the switches one might need to accomplish whatever task is at hand. Personally, I've spent far more time grep'ing my history than using man. And true story, someone may have heard of at one point tcpdump or whatever but not know what man is. There's also people that transcend the platform multiverse that may spend hours, days or weeks building a bash script using linux tools that's used briefly or automated and will require familiarization if that process is ever reviewed/needed again. Tools like this and the regex visualization sites mentioned previously are great for that.
    - gerdesj 8y ago
      To be fair mate: you are spot on. I'll never use it and I'll still be reading the man page and the HTML howtos for a few years to come. That said, someone had a bash and put a spotlight on something. I have lost count of the times I have had to tell people to stop relying on "magic" and get a bloody packet capture out. Oh ... and log files.
    - isostatic 8y ago
      tcpdump is massively useful, I use it on a frequent basis with "-nn -T rtp", and some perl, to analyze missing/out of order RTP packets
- danmg 8y ago
  Looks like this https://i.imgur.com/GO4lqRE.png https://i.imgur.com/GO4lqRE.png

moreira 8y ago

This is incredible and makes me think a website like this could and should exist, containing an interface to as many unix tools as possible. Yes, one could "RTFM" as one commenter mentioned, but if you're just a casual CLI user, this sort of interface seems incredibly handy. "I know I want to use cURL but I don't know what arguments I need to do X and Y". Use the interface to piece together a whole command, with nice instructions for every little flag and argument available so you know what you're doing. It's kind of like those visual regex builders. They're amazing!

raister 8y ago
and then, the next software version will change that -x by -X and all go to the fan.......
- larkeith 8y ago
  For new tools and commands, sure, but most notable Linux utilities are mature and stable, with very few syntactic changes - so many production scripts already rely on syntax remaining static that changing it would break far more than the suggested tool.
  - stefan_ 8y ago
    You would think that. Then, oops, we're running dash, not bash. Or that sinking feeling you get when you think "that command line switch worked last week" on some "mature and stable" Linux utility only to realize that you're no longer running bash with real utilities, but ash with toybox or busybox builtins because some dickhead wanted to save 5 MiB on his docker image.
zorpner 8y ago
A/UX had a tool like this called Commando (you can see it in the third screenshot on this page: http://toastytech.com/guis/aux3.html http://toastytech.com/guis/aux3.html ).
- 8y ago

john37386 8y ago

Cool stuff, I would personally enforce the "count" packet to 100 or 1000 by default. This way, you make sure that no one crashes this powerful device. If someone knows what is doing, then he could just disable it. Sniffing at +10Gbps can be tricky sometimes.

mimsee 8y ago

I'd like to see the source published on github with an Open Source license so I could fix a lot of the UX issues with this page.

orf 8y ago
https://tcpdump101.com/js/t101.js https://tcpdump101.com/js/t101.js 9,000 lines of Javascript, looking pretty handmade and very heavily coupled. I'm not sure if you'd make much progress.
- londons_explore 8y ago
  But on the plus side, at least it isn't gobbling a gig of ram and lagging while react re-renders everything 25 times.
  - orf 8y ago
    And on the downside, it's an unmaintainable mess that would require a rewrite to have any hope of having a usable UI.

myrandomcomment 8y ago

So my first thought was this is really cool, and it is. However I realized I would never use it as if I need tcpdump, I am on a CLI and I am just going to type man for things I need to look up.