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# System prepended metadata

title: 'ISec Assignment 2: Hints and Tricks'

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# ISec Assignment 2: Hints and Tricks

## :rotating_light: Rules :rotating_light:

1. **Do not share direct solutions** or code that can directly be used for the actual task.
2. Make sure to adhere to the definitions of the "Tips" and "Hints" sections, as outlined in "Usage".
3. Only change your own writings, but feel free to add and comment.

## Usage

- There are two main sections: Tips and Hints.
- Tips:
    - Aggregates information that is **not directly necessary to solve the tasks**, but is certainly helpful to do so.
    - It **can be read before** working on the tasks **without spoiling any solutions**.
- Hints:
    - Information here **facilitates finding solutions**.
    - This document should prevent you from wandering cluelessly for hours.
    - For your own learning experience, try to solve issues by yourself.
    - Try Google first.
    - Only if you cannot find the problem or answer yourself, check for possible hints.
    - Otherwise, **you may be spoiled a little and don't learn as much**.

## Tips

### Part 3: TCP Server

#### General

##### Problem: `man 2 recv - No manual entry for ...`

- The program-body suggests to look up specific functions via e.g. `man 2 recv` in the command line.
- For some, this just returns `No manual entry for ...`.
- You may need to install an extended version of the manual. Consult Google.

#### Windows Users

##### Develop directly on Kali Linux

- Windows does not provide some of the used libraries.
- Kali Linux does.
- Thus, you may want to install your IDE of choice directly on the VM.

## Hints

- Make sure to order hints in chronological order, so people do not get spoiled when reading from top to bottom.

### Part 3: TCP server

#### Server does not answer Telnet

- You may tried `telnet 00000101 6666`, but the server did not respond.
- As you probably have seen, `00000101` is translated to the IP `0.0.0.65`.
- Yet, is an IP usually 8 bit long?
- How long should it be?
- Is this a valid IP address within the network?
- Find out the network's address space. Try `ip a`.
- Maybe the given address lacks the network's prefix?