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--- home_server:home_server_setup:other_services:ssh [2022-06-26 Sun wk25 09:13] – baumkp
+++ home_server:home_server_setup:other_services:ssh [2025-01-10 Fri wk02 10:59] (current) – [Some Links:] baumkp
@@ Line 1: / Line 1: @@
+{{tag>linux debian ssh "ssh notes"}}
 ======SSH Notes======
+=====SSH Login Message=====
+====Acronyms and Definitions====
+  *MOTD = Message of the Day
+====Login Messages====
+  *''sudo vim /etc/issue.net'' Displays a message before the user begins login, I do not use this.
+    *''sudo vim /etc/ssh/sshd_config'' ensure the following option is set ''Banner /etc/issue.net'' (you can actually used any path/file)
+    *''sudo systemctl reload sshd'' needs to be performed after any change to the configuration file to activate the changes.
+  *''sudo vim /etc/motd'' Displays the banner text after login. This usually has some predefined Linux distribution text
+====Login Scripts====
+====Debian====
+  *''ls -la /etc/update-motd.d/'' to see the scripts that are run after the MOTD is displayed.
+The Debian script is very simple:
+<code bash>
+#!/bin/sh
+uname -snrvm
+</code>
+====Ubuntu====
+Ubuntu has multiple scripts some that I like and some that I do not like.
+This system status information script, ++++/etc/update-motd.d/50-landscape-sysinfo|
+<code>
+#!/bin/sh
+# pam_motd does not carry the environment
+[ -f /etc/default/locale ] && . /etc/default/locale
+export LANG
+cores=$(grep -c ^processor /proc/cpuinfo 2>/dev/null)
+[ "$cores" -eq "0" ] && cores=1
+threshold="${cores:-1}.0"
+if [ $(echo "`cut -f1 -d ' ' /proc/loadavg` < $threshold" | bc) -eq 1 ]; then
+    echo
+    echo -n "  System information as of "
+    /bin/date
+    echo
+    /usr/bin/landscape-sysinfo
+else
+    echo
+    echo " System information disabled due to load higher than $threshold"
+fi</code>
+++++
+The main information script is written in python3, ++++/usr/bin/landscape-systeminfo|
+<code>
+#!/usr/bin/python3
+import sys, os
+try:
+    if os.path.dirname(os.path.abspath(sys.argv[0])) == os.path.abspath("scripts"):
+        sys.path.insert(0, "./")
+    else:
+        from landscape.lib.warning import hide_warnings
+        hide_warnings()
+    from twisted.internet import reactor
+    from landscape.sysinfo.deployment import run
+except ImportError:
+    # For some reasons the libraries are not importable for now. We are
+    # probably during an upgrade procedure, so let's exit, expecting the
+    # dependencies to be fixed at next run.
+    sys.exit(2)
+if __name__ == "__main__":
+    run(sys.argv[1:], reactor)
+</code>
+  *If twisted not installed, ''pip install twisted'' to install
+  *if cpuinfo not installed, ''pip install py-cpuinfo'' to install
+++++
+====Python Code====
+++++python3 agnostic code |
+<code>
+#!/usr/bin/python3
+import psutil
+import platform
+from datetime import datetime
+import cpuinfo
+import socket
+import uuid
+import re
+def get_size(bytes, suffix="B"):
+    """
+    Scale bytes to its proper format
+    e.g:
+        1253656 => '1.20MB'
+        1253656678 => '1.17GB'
+    """
+    factor = 1024
+    for unit in ["", "K", "M", "G", "T", "P"]:
+        if bytes < factor:
+            return f"{bytes:.2f}{unit}{suffix}"
+        bytes /= factor
+def System_information():
+    print("="*40, "System Information", "="*40)
+    uname = platform.uname()
+    print(f"System: {uname.system}")
+    print(f"Node Name: {uname.node}")
+    print(f"Release: {uname.release}")
+    print(f"Version: {uname.version}")
+    print(f"Machine: {uname.machine}")
+    print(f"Processor: {uname.processor}")
+    print(f"Processor: {cpuinfo.get_cpu_info()['brand_raw']}")
+    print(f"Ip-Address: {socket.gethostbyname(socket.gethostname())}")
+    print(f"Mac-Address: {':'.join(re.findall('..', '%012x' % uuid.getnode()))}")
+    # Boot Time
+    print("="*40, "Boot Time", "="*40)
+    boot_time_timestamp = psutil.boot_time()
+    bt = datetime.fromtimestamp(boot_time_timestamp)
+    print(f"Boot Time: {bt.year}/{bt.month}/{bt.day} {bt.hour}:{bt.minute}:{bt.second}")
+    # print CPU information
+    print("="*40, "CPU Info", "="*40)
+    # number of cores
+    print("Physical cores:", psutil.cpu_count(logical=False))
+    print("Total cores:", psutil.cpu_count(logical=True))
+    # CPU frequencies
+    cpufreq = psutil.cpu_freq()
+    print(f"Max Frequency: {cpufreq.max:.2f}Mhz")
+    print(f"Min Frequency: {cpufreq.min:.2f}Mhz")
+    print(f"Current Frequency: {cpufreq.current:.2f}Mhz")
+    # CPU usage
+    print("CPU Usage Per Core:")
+    for i, percentage in enumerate(psutil.cpu_percent(percpu=True, interval=1)):
+        print(f"Core {i}: {percentage}%")
+    print(f"Total CPU Usage: {psutil.cpu_percent()}%")
+    # Memory Information
+    print("="*40, "Memory Information", "="*40)
+    # get the memory details
+    svmem = psutil.virtual_memory()
+    print(f"Total: {get_size(svmem.total)}")
+    print(f"Available: {get_size(svmem.available)}")
+    print(f"Used: {get_size(svmem.used)}")
+    print(f"Percentage: {svmem.percent}%")
+    print("="*20, "SWAP", "="*20)
+    # get the swap memory details (if exists)
+    swap = psutil.swap_memory()
+    print(f"Total: {get_size(swap.total)}")
+    print(f"Free: {get_size(swap.free)}")
+    print(f"Used: {get_size(swap.used)}")
+    print(f"Percentage: {swap.percent}%")
+    # Disk Information
+    print("="*40, "Disk Information", "="*40)
+    print("Partitions and Usage:")
+    # get all disk partitions
+    partitions = psutil.disk_partitions()
+    for partition in partitions:
+        print(f"=== Device: {partition.device} ===")
+        print(f"  Mountpoint: {partition.mountpoint}")
+        print(f"  File system type: {partition.fstype}")
+        try:
+            partition_usage = psutil.disk_usage(partition.mountpoint)
+        except PermissionError:
+            # this can be catched due to the disk that
+            # isn't ready
+            continue
+        print(f"  Total Size: {get_size(partition_usage.total)}")
+        print(f"  Used: {get_size(partition_usage.used)}")
+        print(f"  Free: {get_size(partition_usage.free)}")
+        print(f"  Percentage: {partition_usage.percent}%")
+    # get IO statistics since boot
+    disk_io = psutil.disk_io_counters()
+    print(f"Total read: {get_size(disk_io.read_bytes)}")
+    print(f"Total write: {get_size(disk_io.write_bytes)}")
+    ## Network information
+    print("="*40, "Network Information", "="*40)
+    ## get all network interfaces (virtual and physical)
+    if_addrs = psutil.net_if_addrs()
+    for interface_name, interface_addresses in if_addrs.items():
+        for address in interface_addresses:
+            print(f"=== Interface: {interface_name} ===")
+            if str(address.family) == 'AddressFamily.AF_INET':
+                print(f"  IP Address: {address.address}")
+                print(f"  Netmask: {address.netmask}")
+                print(f"  Broadcast IP: {address.broadcast}")
+            elif str(address.family) == 'AddressFamily.AF_PACKET':
+                print(f"  MAC Address: {address.address}")
+                print(f"  Netmask: {address.netmask}")
+                print(f"  Broadcast MAC: {address.broadcast}")
+    ##get IO statistics since boot
+    net_io = psutil.net_io_counters()
+    print(f"Total Bytes Sent: {get_size(net_io.bytes_sent)}")
+    print(f"Total Bytes Received: {get_size(net_io.bytes_recv)}")
+if __name__ == "__main__":
+    System_information()
+</code>
+++++
+====Some Links:====
+  *[[https://www.simplified.guide/ssh/suppress-banner|How to manage SSH login message]]
+  *[[https://www.shellhacks.com/setup-warning-message-banner-ssh/|HowTo: Set a Warning Message (Banner) in SSH]]
+  *[[https://www.tecmint.com/protect-ssh-logins-with-ssh-motd-banner-messages/|Protect SSH Logins with SSH & MOTD Banner Messages]]
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