> For the complete documentation index, see [llms.txt](https://kchuene.gitbook.io/data-communication-project/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kchuene.gitbook.io/data-communication-project/troubleshooting.md). # Troubleshooting Commands to mostly help you troubleshoot configuration issues. ## Kali **/usr/bin/nmap: 6: exec: /usr/lib/nmap/nmap: Operation not permitted** The error occurs when trying to run `nmap` within the **Kali Linux Docker** container. Run the following command to resolve the issue. {% code overflow="wrap" lineNumbers="true" %} ``` setcap cap_net_raw,cap_net_bind_service+eip /usr/lib/nmap/nmap ``` {% endcode %} ## SSH **PasswordAuthentication set to "no" but not taking effect** Configs inside `/etc/ssh/sshd_config.d/` take pre-emminence over the `/etc/ssh/sshd_config` because of the line {% code overflow="wrap" lineNumbers="true" %} ``` Include /etc/ssh/sshd_config.d/*.conf ``` {% endcode %} which appears at the beginning of `/etc/ssh/sshd_config` file. The `/etc/ssh/sshd_config` is not meant to be modified directly, rather make configuration changes in a custom `.conf` file inside the `/etc/ssh/sshd_config.d/` directory and they will take effect on a **First Match Rule** over those of `sshd_config` . The following command can be used to see if your editions take effect {% code overflow="wrap" lineNumbers="true" %} ``` sudo sshd -T | grep PasswordAuthentication ``` {% endcode %} ## General **If no nano or vi (vim) text editor** Use the `tee` command {% code overflow="wrap" lineNumbers="true" %} ``` tee output.txt < Settings > Storage > [Guest Name].vdi > Check Solid-state Drive ``` {% endcode %} {% hint style="info" %} Faster and more stable booting from what I noticed. {% endhint %} **Issue of not having root or sudo access after Ubuntu Desktop installation** Don't use **unattended installation** on **Virtualbox**, rather install Ubuntu manually. You should get the following message the first time you open the terminal. ``` To run a command as administrator (user "root"), use "sudo ". See "man sudo_root" for details. ``` **Create a new NAT Network adapter** ``` File > Tools > Network Manager > NAT Networks > Create ``` **Expanding an existing dynamic virtual disk** In **Virtualbox**: {% code overflow="wrap" lineNumbers="true" %} ``` File > Tools > Virtual Media Manager > (Select one) > Properties > Attributes ``` {% endcode %} {% hint style="warning" %} Make sure you expand the listed hard disk to also increase the size of nested disks, eg. **{xxxx-xxxx-xxx}.vdi** files and not just **Ubuntu-Dektop.vdi.** There is probably one **.vdi** file for every snapshot. {% endhint %} Have the OS use the available space by resizing the partition and filesystem {% code overflow="wrap" lineNumbers="true" %} ``` # 1. Get filesystem size relative to available disk space df -h / lsblk # 2. Resize partition number 3 (sda3) of disk sda sudo parted /dev/sda (parted) print free (parted) resizepart 1 100% (parted) quit # 3. Resize filesystem (/ mounted on sda3) to size of partition (full size by default) sudo resize2fs /dev/sda3 # 4. Verify df -h / lsblk ``` {% endcode %} {% hint style="info" %} When asked to "fix the GPT to use all of the space" enter "Fix". {% endhint %} {% code overflow="wrap" lineNumbers="true" %} ``` // Alternate command sequence df -h / lsblk sudo parted /dev/sda print sudo parted /dev/sda resizepart 3 100% sudo resize2fs /dev/sda3 df -h lsblk ``` {% endcode %} ## Network **Monitor network traffic (communication) with tcpdump** {% code overflow="wrap" lineNumbers="true" %} ``` tcpdump -i enp0s3 dst port 9880 or dst port 22 ``` {% endcode %} **View open ports** ``` ss -tlnp ``` **Restart a network interface** ``` sudo ip link set enp0s3 down sudo ip link set enp0s3 up ``` ## Host Services **Check Configuration Loaded by Systemd Service** ``` systemctl cat wazuh-agent ``` **Check any service's status** ``` systemctl status service-name ``` **Check connection status to a specific port** ``` watch -n 1 'ss -tnp | grep :9880' ``` **View service logs after it failed** ``` journalctl -u wazuh-agent ``` **View service logs live** ``` journalctl -u wazuh-agent ``` ## Docker Containers **Attach to a container** {% code overflow="wrap" lineNumbers="true" %} ``` sudo docker attach my-container ``` {% endcode %} **Clearing unused volumes (data left behind by removed applications)** {% code overflow="wrap" lineNumbers="true" %} ``` sudo docker volume prune -a ``` {% endcode %} **View environment variables of a container (specifically useful to see $PATH and the like, ie. what commands in the container)** {% code overflow="wrap" %} ``` sudo docker inspect --format='{{range .Config.Env}}{{println .}}{{end}}' my-container ``` {% endcode %} **View open ports within distroless containers (uses host binaries)** {% code overflow="wrap" %} ``` sudo docker inspect -f '{{.State.Pid}}' cowrie # Gets container PID ``` {% endcode %} {% code overflow="wrap" %} ``` sudo nsenter -t 1353 -n ss -tlnp # Enter network (ss) namespace and run ss ``` {% endcode %} **Check containers' statuses** ``` sudo docker ps ``` **Recreate images for services to reload env or changes to compose config** ``` sudo docker compose up --force-recreate ``` **View logs of a container** ``` sudo docker logs 84006cac987 # container-id ``` **Deleting unused containers** ``` sudo docker container ls -a sudo docker container prune ``` **Attaching a shell to a container or running a command (useful for getting a view of the container filesystem)** ``` sudo docker exec -it mycontainer /bin/bash sudo docker exec mycontainer ls -la / ``` ## Miscellaneous **Run a process in the background (since ubuntu server does not come with multi-window terminal)** ``` nc -lvp 9880 & ``` --- # Agent Instructions This documentation is published with GitBook. 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