Use SSH, ARD, SNMP, And The Server App Remotely On OS X Server 5
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If you use CLI: [email protected]> enable[email protected]# configure[email protected] (Config)# snmp-server community "public" ro[email protected] (Config)# snmp-server sysname "devicename"[email protected] (Config)# snmp-server contact "[email protected]"[email protected] (Config)# exit[email protected]# write memory
Simple Network Management Protocol (SNMP) is an Internet Standard protocol for collecting and organizing information about managed devices on IP networks and for modifying that information to change device behaviour. Devices that typically support SNMP include cable modems, routers, switches, servers, workstations, printers, and more.[1]
A managed device is a network node that implements an SNMP interface that allows unidirectional (read-only) or bidirectional (read and write) access to node-specific information. Managed devices exchange node-specific information with the NMSs. Sometimes called network elements, the managed devices can be any type of device, including, but not limited to, routers, access servers, switches, cable modems, bridges, hubs, IP telephones, IP video cameras, computer hosts, and printers.
In an enterprise environment, servers and workstations can be organized into domains. Domains provide centralized identity management, allowing users to login using one set of credentials across the entire network. If an adversary is able to obtain a set of valid domain credentials, they could login to many different machines using remote access protocols such as secure shell (SSH) or remote desktop protocol (RDP).[1][2]
Connect devices directly to this small form-factor console server via 8 serial and 4 USB ports, providing always-on access to your remote networking equipment. Every model includes 4GB internal memory. Options include a 4-port GbE switch and models without the cellular modem.
User management configurationFrom AXIS OS 10.9 and onwards, user configuration related changes are logged in the system log and can therefore be sent to a remote syslog server. In AXIS OS, VAPIX and ONVIF users are separated by having their own management interfaces and access rights. The below table illustrates what log messages to expect when certain changes to the user management configuration are done:
Self-Signed CertificateAxis products with support for TPM module or Software keystore only generate a self-signed certificate during first-boot up. Axis devices come with a pre-installed self-signed certificate in order to provide the possibility to access the device via encrypted HTTPS connection and proceed with the initial setup of the device. Since the first-boot certificate is self-signed by the device, it is not suitable for providing authentication or authenticity against networks and applications. Therefore, Axis recommends removing the self-signed certificate from the device and replace it with a server certificate that is trusted in your organization when HTTPS connection is the preferred type of connection to the device.
CA certificatesCA certificates are certificates used by the Axis device to validate/verify the authenticity of other servers in the network. This means that CA certificates that are going to be uploaded in the CA certificate section of the Axis device need to fulfil one of the following:
The number of unique encoded streams tells us how many different video streams an Axis device is encoding. This information can be obtained in the server report of devices with firmware version 5.70 or higher in the section Snapshot of the current (caching) streams. For devices with AXIS OS version 10.7 or higher, this information is available in the section Snapshot of all running streams. The number of unique encoded streams are affected by stream properties, as will be shown in the examples below. Note that the illustrations are taken from a graphical user interface to better illustrate the use case.
This information can be obtained in the server report of devices with firmware version 9.80 and higher in the section Snapshots of the current outgoing RTP streams. This section lists the number of distributed streams in relation to their destination IP address. The distributed stream is declared as a ratio of Number of video streams:Number of physical network clients.
Have in mind that action rules allocate a video source buffer once the action rule is activated. This means that even though the Axis device is supposed to send an image to an FTP server once a day, it will result in the video source buffer being allocated for the entire day
Network Time Protocol is used to synchronize computer clocks on the Internet or in local networks. Version 4 (NTPv4) is the current version and is described by RFC 5904. It's fully compatible with NTPv3 and all previous versions and is designed to support the IPv6 protocol and dynamic server discovery. NTP is utilizing UDP as a transport protocol via port 123, which means that package delivery cannot be guaranteed.
NTP uses a hierarchical structure where several NTP servers operating on different levels and accuracy (=stratum) are synced against each other to provide accurate time syncs to network devices. To do so, an NTP server in the network that provides time to local network devices should always sync to one or more NTP servers higher up in the hierarchy to avoid time-fluctuation and increased time accuracy. However, it's possible to operate an NTP server locally in a network in a standalone mode if no other NTP servers are available. More information about how the NTP protocol works can be obtained from public sources such as Wikipedia.
Axis devices with AXIS OS 11.1 or higher support Network Time Security. NTS allows the devices to get time from a trusted source. NTS is a mechanism for using Transport Layer Security (TLS) and Authenticated Encryption with Associated Data (AEAD) to provide cryptographic security for the client-server mode of the NTP.
NTS Key Exchange (KE): Exchange the necessary keys between the NTP client and server via Transport Layer Security (TLS). Once key exchanges are done, the TLS channel will be closed. The NTP client also knows which NTP server to query.
The following sections illustrate the steps taken during a complete NTP synchronization while using OpenNTPD. This network trace can be used as a reference for below steps and shows a complete NTP synchronization from the first phase until the Axis device is in full NTP sync with the configured NTP server.
Phase 1: It starts with the initial time query. The very first time-sync from an Axis device to an NTP server is a "universal sync" which means that any time provided by the NTP server will be taken by the Axis device as system time. Phase 1 is usually initiated when configuring the Axis device to sync against an NTP server (enable NTP), when the Axis device is restarted or when a firmware upgrade is initiated that also results in a restart of the Axis device.
Phase 3: Phase 3 is considered the usual operation mode. The query interval will stabilize after phase 2 between 30 - 1500 s + 10 % randomization apart. In case the time difference increases during normal operation mode, the device will shorten the interval to sync more often in order to compensate for this. And if the time drift is very small, the intervals between two syncs will be larger. Note that the sync state is changing to "Yes", which indicates that the Axis device is in good time-sync with the configured NTP server.
Phase 2: Phase 2 is considered the usual operation mode. Once the time is synchronized, the general query polling interval to the NTP server is set to 64 seconds.Most of the Axis devices have a built-in real-time clock (RTC). The system will copy the clock from the RTC on the boot. To maintain the accuracy of the RTC, we enabled chronyd to copy the system time to the RTC every 11 minutes. Please be aware that chronyd will not track RTC drift.One of the main activities of the chronyd program is to work out the rate at which the system clock gains or loses time relative to real time. Whenever chronyd computes a new value of the gain or loss rate, it will record the value at /var/lib/chrony/drift. This can also help stabilize the initial synchronization on the next start.
To configure NTS, go to System > Date and time, and select Automatic date and time (manual NTS KE servers).You can either input the IP address of the NTP KE servers or the hostname (make sure the DNS server is properly configured). Here is an example of successful time sync via NTS:
Phase 1The Chrony client starts communicating with the KE server by establishing a TLS channel. That follows the key exchange. In the key exchange process, the client receives secret keys and cookies to be used later. The cookies contain secret keys only understood by the NTP server. The KE server also notifies the client which NTP server to query. Once the exchange is done, the TLS channel will be terminated.
Phase 2The Chrony client directly contacts the NTP server. It encrypts the query by the key it gets from phase 1. In that query, a cookie is also included. Once the server receives the query, it knows how to read the query. The server will respond to the client with a signed query. The client validates the signature in the incoming packet and then sets the time knowing it was sent from the correct server.
The following common log messages from Axis devices can be seen during NTP/NTS time-sync operations as well as during certain error conditions, e.g. if the NTP/NTS server is not operating correctly or cannot be reached. The log messages and their explanations provide a great detail of information on how the NTP/NTS protocol is working in practice. Plus, it's good to get an understanding of the log messages when troubleshooting NTP/NTS protocol related issues.
The delay in an NTP server describes the round-trip delay or latency of a timing message passed from client to server and back again. The delay is important so that network delays can be calculated and accounted for by the NTPd process of the Axis device. 2b1af7f3a8