4 ms·

I want to get some hands on experience with networking and am looking for a side project. Do you have any suggestions or know of any projects that I can use for

by zests 6y ago

I want to get some hands on experience with networking and am looking for a side project. Do you have any suggestions or know of any projects that I can use for inspiration?

imglorp 6y ago
It doesn't take much to get started. A good start for reading is the concepts around IP, especially how protocols can encapsulate each other, also known as layers. Skim [1] maybe. The definitive reference used to be the W. Richard Stevens books cited there. Next pick a fun, simple protocol you're interested in. Consider ICMP, Echo, DNS, or if you like NTP, see OP's fine writeup to repeat the experiments. Skim the IETF RFC [2] for your protocol, especially the bitmap diagram. Install Wireshark and play around dissecting packets on your network, noting how it shows you the layers and bitfields as above. The most important step is to write some toy code for a client, server, or peer for your fun protocol. As above Erlang makes it simple to take apart packets directly referring to the bitfield diagrams, but most stacks should have a packet inspection library you can mess with. Wireshark will help watch your work. Another good thing to learn is routing. If you have a BSD or Linux box or a Raspberry Pi, learn some IPTables or BPF [3]. Play around with writing your own firewall rules on your box. Play with how the OS sees networking, ie netstat, arp, and route outputs. 1. https://en.wikipedia.org/wiki/Internet_protocol_suite https://en.wikipedia.org/wiki/Internet_protocol_suite 2. https://ietf.org/standards/rfcs https://ietf.org/standards/rfcs 3. http://www.brendangregg.com/ebpf.html http://www.brendangregg.com/ebpf.html
- StreamBright 6y ago
  The next protocol is DNS! :) It is a bit tricky but I have the working parser for the header. Looking into how I could parse qname with that octet thing going on. https://github.com/n0hup/elafi/blob/master/apps/dnscache/lib/dnscache/server.ex#L27 https://github.com/n0hup/elafi/blob/master/apps/dnscache/lib... It will be running on raspberry nodes (kind of replacing Pihole).
  - imglorp 6y ago
    Nice. How do you feel about Elixir, seeing as how you're working in both? I'm happy with straight erl but always curious about the other grass.
    - StreamBright 6y ago
      Since I learned Erlang first and I really like it I have no issues with its syntax. I do not even understand people complaining about it. Elixir is just Ruby(ish) syntax on the top, it does not add anything (or takes away anything) at least to me. I write a lot of F# so I think I probably like it because Elixir took some of the features from F# (or ML languages). It is nice to have a pipe operator. One piece of functionality that is nice to have is fmt. You can format your code before committing to the repo, this takes away some of the bikeshed arguments. Other than that I am not using much from Elixir. Jose is a really smart Erlang guy though. He used to hang out on IRC and StackOverflow answering Erlang questions. Straight Erlang is fine.
StreamBright 6y ago
hi @zest, I am working on a DNS filter in Elixir if you are interested.

by zests 6y ago

I want to get some hands on experience with networking and am looking for a side project. Do you have any suggestions or know of any projects that I can use for inspiration?

imglorp 6y ago

It doesn't take much to get started. A good start for reading is the concepts around IP, especially how protocols can encapsulate each other, also known as layers. Skim [1] maybe. The definitive reference used to be the W. Richard Stevens books cited there. Next pick a fun, simple protocol you're interested in. Consider ICMP, Echo, DNS, or if you like NTP, see OP's fine writeup to repeat the experiments. Skim the IETF RFC [2] for your protocol, especially the bitmap diagram. Install Wireshark and play around dissecting packets on your network, noting how it shows you the layers and bitfields as above. The most important step is to write some toy code for a client, server, or peer for your fun protocol. As above Erlang makes it simple to take apart packets directly referring to the bitfield diagrams, but most stacks should have a packet inspection library you can mess with. Wireshark will help watch your work. Another good thing to learn is routing. If you have a BSD or Linux box or a Raspberry Pi, learn some IPTables or BPF [3]. Play around with writing your own firewall rules on your box. Play with how the OS sees networking, ie netstat, arp, and route outputs. 1. https://en.wikipedia.org/wiki/Internet_protocol_suite https://en.wikipedia.org/wiki/Internet_protocol_suite 2. https://ietf.org/standards/rfcs https://ietf.org/standards/rfcs 3. http://www.brendangregg.com/ebpf.html http://www.brendangregg.com/ebpf.html

StreamBright 6y ago
The next protocol is DNS! :) It is a bit tricky but I have the working parser for the header. Looking into how I could parse qname with that octet thing going on. https://github.com/n0hup/elafi/blob/master/apps/dnscache/lib/dnscache/server.ex#L27 https://github.com/n0hup/elafi/blob/master/apps/dnscache/lib... It will be running on raspberry nodes (kind of replacing Pihole).
- imglorp 6y ago
  Nice. How do you feel about Elixir, seeing as how you're working in both? I'm happy with straight erl but always curious about the other grass.
  - StreamBright 6y ago
    Since I learned Erlang first and I really like it I have no issues with its syntax. I do not even understand people complaining about it. Elixir is just Ruby(ish) syntax on the top, it does not add anything (or takes away anything) at least to me. I write a lot of F# so I think I probably like it because Elixir took some of the features from F# (or ML languages). It is nice to have a pipe operator. One piece of functionality that is nice to have is fmt. You can format your code before committing to the repo, this takes away some of the bikeshed arguments. Other than that I am not using much from Elixir. Jose is a really smart Erlang guy though. He used to hang out on IRC and StackOverflow answering Erlang questions. Straight Erlang is fine.

StreamBright 6y ago

hi @zest, I am working on a DNS filter in Elixir if you are interested.