How to restart the networking service in Linux

The main reason why Windows cannot see the Samba share is that the firewall blocks UDP137–139/TCP445 or NetBIOS name resolution fails; it is necessary to confirm that the workgroup is consistent, the interfaces are configured correctly, the file permissions match forceuser/forcegroup, and set doscharset=UTF-8 to solve Chinese garbled characters.

Logical volumes and file systems can be expanded online. You need to expand the LV first and then the file system. It is recommended to use lvextend-r for automatic synchronization adjustment, but you must ensure that the LVM and file system tool versions are compatible.

Netstat displays fewer LISTEN ports than ss because it does not display process information by default that non-root users do not have access to; ss can read all listening sockets by default without process names, and sudonetstat-tulpn is required to display them completely.

When fdisk is stuck at the Command prompt, it is normally waiting for input. Enter q to exit safely; you must umount before mkfs, otherwise it may fail silently; partedmkpart does not support the specified file system type, and mkfs needs to be executed separately.

It is recommended to use ssh-keygen-ted25519 to generate a key pair, because it is faster, more secure, and has a shorter key than the default RSA; it is necessary to strictly set the ~/.ssh directory permissions to 700 and authorized_keys to 600, and use ssh-v to confirm whether the client is Offering public key and whether the server rejects it.

Netplan reports "InvalidYAML" when configuring a static IP due to indentation errors, missing spaces after colons, or mixed tabs; gateway4 has been deprecated and routes to:default must be used instead; NetworkManager needs to be modified before down/up takes effect; the renderer field is used to determine the backend during coexistence; incorrect DNS configuration will cause ping to succeed but curl to fail.

The applicable scenarios of VNC and XRDP are different: VNC is suitable for complete graphics, multi-user, and cross-platform. Tigervnc-server is recommended and xstartup and port are correctly configured;

There is no response when pressing e because GRUB has enabled superusers or password_pbkdf2 authentication, and you need to execute setsuperusers="" and unsetpassword on the command line to bypass it; when changing init=/bin/bash, you must add rw at the same time, otherwise the root file system will be read-only and cause failure; when passwd reports an error, you need to check the mounting status and SELinux, and run sync before exec to ensure that the password is written to the disk.