Terminal & SNMP

The SNMP Options in Control Terminal allow you to enter using the Telnet and SSH command line interface services, and Synology NAS monitors using network management software. Enabling options in Control Panel> Terminal & SNMP> Terminal allows your Synology NAS to support SSH and Telnet command line interface services.

To enable the Telnet / SSH service: Check the box next to the desired protocol (SSH or Telnet). Click Apply. To change the SSH service port: In Port, enter the new port number. Click Apply. Various encryption algorithms with different levels of security are used to secure SSH connections. You can decide which algorithm is best used to meet your needs.

To change the security level of the SSH encryption algorithm: Click Advanced Settings. Select the security level for the encryption algorithm. If you want to determine exactly which algorithm can be used, select Customization to choose from three groups: Cipher, KEX (Key Exchange), and MAC (Message Authentication Code). Click Apply. 

Some models support hardware acceleration for certain encryption algorithms. You can check the options. Only use accelerated hardware ciphers to increase the speed of transfer of SSH related services, including encrypted Network Backup and SFTP services. On the advanced page, algorithms capable of using hardware acceleration are shown in red.

Some services (eg network backup, SFTP) automatically enable SSH and open port 22. In this case, you must enable SSH services in Control Panel> Terminal & SNMP> Terminal to enter DSM using SSH. SSH / Telnet only supports logging into systems with accounts belonging to the local administrator group. 

To switch to the root account, please enter the system with SSH / Telnet as a user belonging to the local administrator group, run the sudo -i command, and then enter the account password used to enter. Password cannot be left blank when entering the system with SSH / Telnet.

When the SSH service is disabled, all SSH connections are terminated, including the task of backing up the encrypted network that is running. We recommend doing network backup tasks again after the SSH service is disabled. Incorrect manipulation or modification of Synology NAS can cause malfunction or data loss.

Choosing a higher level of security or just using a hardware-accelerated password can cause some SSH clients to be unable to connect due to compatibility issues. Depending on the level of security chosen, certain algorithms that support hardware acceleration may not be available.

Terminal System & SNMP Database

Synology NAS uses a system database to track package data and system log entries stored on shared folders created on your external storage device, such as usbshare1.

Important: If you want to access packet data stored on an external storage device installed on your Synology NAS, or if you want to see DSM log records in the Main Menu> Center Log, the system database must be activated first. Otherwise, all related services cannot be accessed.

To activate the system database: Check Activate system database. Do one of the following: Select Automatic configuration if you want DSM to automatically select shared folders to save the system database. If an external storage device containing shared folders is deleted, the DSM will automatically select other shared folders to save the database in Terminal and SNMP.

Select Move the current database to the selected shared folder, then select from the drop-down menu to move the current database to other shared folders created on your external device. Select Select one from the existing database, and then select it from the drop-down menu to select an existing database if there are more than one external device connected to your Synology NAS. 

Click Apply. Warning: To prevent the database from being damaged, make sure you have removed the storage device in the Main Menu> Control Panel> External Devices> External Devices or by clicking on the external device icon in the upper right corner before releasing it from Synology NAS Terminal  and SMNP.