Add full Linux practice report with configs and screenshots

application/http_shefler_server_service.service

@@ -0,0 +1,12 @@
+[Unit]
+Description=HTTP_Shefler_server_5000
+After=network.target
+
+[Service]
+User=shefler_1
+WorkingDirectory=/opt/http_shefler_server
+ExecStart=/usr/bin/python3 /opt/http_shefler_server/shefler_5000.py
+Restart=always
+
+[Install]
+WantedBy=multi-user.target

application/shefler_5000.py

@@ -0,0 +1,20 @@
+from flask import Flask, request, jsonify
+
+app = Flask(__name__)
+
+@app.route('/get', methods=['GET'])
+def get():
+    return jsonify({"method": "GET", "message": "Get response"}), 200
+
+@app.route('/post', methods=['POST'])
+def post():
+    data = request.get_json()
+    return jsonify({"method": "POST", "received": data}), 200
+
+@app.route('/put', methods=['PUT'])
+def put():
+    data = request.get_json()
+    return jsonify({"method": "PUT", "received": data}), 200
+
+if __name__ == "__main__":
+    app.run(host="0.0.0.0", port=5000)

configs/LinuxA/00-installer-config.yaml

@@ -0,0 +1,10 @@
+# This is the network config written by 'subiquity'
+network:
+  ethernets:
+    enp0s3:
+      dhcp4: true
+    enp0s8:
+      dhcp4: no
+      addresses: [192.168.16.10/24]
+      gateway4: 192.168.16.1
+  version: 2

configs/LinuxA/http_shefler_server_service.service

@@ -0,0 +1,12 @@
+[Unit]
+Description=HTTP_Shefler_server_5000
+After=network.target
+
+[Service]
+User=shefler_1
+WorkingDirectory=/opt/http_shefler_server
+ExecStart=/usr/bin/python3 /opt/http_shefler_server/shefler_5000.py
+Restart=always
+
+[Install]
+WantedBy=multi-user.target

configs/LinuxB/00-installer-config.yaml

@@ -0,0 +1,12 @@
+# This is the network config written by 'subiquity'
+network:
+  ethernets:
+    enp0s3:
+      dhcp4: true
+    enp0s8:
+      dhcp4: no
+      addresses: [192.168.16.1/24]
+    enp0s9:
+      dhcp4: no
+      addresses: [192.168.3.1/24]
+  version: 2

configs/LinuxB/15-ip4tables

@@ -0,0 +1,84 @@
+#!/bin/sh
+
+# This file is part of netfilter-persistent
+# (was iptables-persistent)
+# Copyright (C) 2009, Simon Richter <sjr@debian.org>
+# Copyright (C) 2010, 2014 Jonathan Wiltshire <jmw@debian.org>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation, either version 3
+# of the License, or (at your option) any later version.
+
+set -e
+
+PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+
+# Source configuration
+if [ -f "/etc/default/netfilter-persistent" ]; then
+    . /etc/default/netfilter-persistent
+fi
+
+load_rules()
+{
+    if [ "${IPTABLES_RESTORE_NOFLUSH}x" = "yesx" ]; then
+        NOFLUSH='--noflush'
+    else
+        NOFLUSH=''
+    fi
+
+    #load IPv4 rules
+    if [ ! -f /etc/iptables/rules.v4 ]; then
+        echo "Warning: skipping IPv4 (no rules to load)"
+    else
+        iptables-restore $NOFLUSH < /etc/iptables/rules.v4
+    fi
+}
+
+save_rules()
+{
+    if [ ! "${IPTABLES_SKIP_SAVE}x" = "yesx" ]; then
+        touch /etc/iptables/rules.v4
+        chmod 0640 /etc/iptables/rules.v4
+        iptables-save > /etc/iptables/rules.v4
+    fi
+}
+
+flush_rules()
+{
+    TABLES=$(iptables-save | sed -E -n 's/^\*//p')
+    for table in $TABLES
+    do
+        CHAINS=$(iptables-save -t $table | sed -E -n 's/^:([A-Z]+).*/\1/p')
+        for chain in $CHAINS
+        do
+            # policy can't be set on user-defined chains
+            iptables -t $table -P $chain ACCEPT || true
+        done
+        iptables -t $table -F
+        iptables -t $table -Z
+        iptables -t $table -X
+    done
+}
+
+case "$1" in
+start|restart|reload|force-reload)
+    load_rules
+    ;;
+save)
+    save_rules
+    ;;
+stop)
+    # Why? because if stop is used, the firewall gets flushed for a variable
+    # amount of time during package upgrades, leaving the machine vulnerable
+    # It's also not always desirable to flush during purge
+    echo "Automatic flushing disabled, use \"flush\" instead of \"stop\""
+    ;;
+flush)
+    flush_rules
+    ;;
+*)
+    echo "Usage: $0 {start|restart|reload|force-reload|save|flush}" >&2
+    exit 1
+    ;;
+esac

configs/LinuxB/25-ip6tables

@@ -0,0 +1,87 @@
+#!/bin/sh
+
+# This file is part of netfilter-persistent
+# (was iptables-persistent)
+# Copyright (C) 2009, Simon Richter <sjr@debian.org>
+# Copyright (C) 2010, 2014 Jonathan Wiltshire <jmw@debian.org>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation, either version 3
+# of the License, or (at your option) any later version.
+
+set -e
+
+PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+
+# Exit fast if IPv6 is disabled
+test -e /proc/sys/net/ipv6 || exit 0
+
+# Source configuration
+if [ -f "/etc/default/netfilter-persistent" ]; then
+    . /etc/default/netfilter-persistent
+fi
+
+load_rules()
+{
+    if [ "${IP6TABLES_RESTORE_NOFLUSH}x" = "yesx" ]; then
+        NOFLUSH='--noflush'
+    else
+        NOFLUSH=''
+    fi
+
+    #load IPv6 rules
+    if [ ! -f /etc/iptables/rules.v6 ]; then
+        echo "Warning: skipping IPv6 (no rules to load)"
+    else
+        ip6tables-restore $NOFLUSH < /etc/iptables/rules.v6
+    fi
+}
+
+save_rules()
+{
+    if [ ! "${IP6TABLES_SKIP_SAVE}x" = "yesx" ]; then
+        touch /etc/iptables/rules.v6
+        ip6tables-save > /etc/iptables/rules.v6
+        chmod 0640 /etc/iptables/rules.v6
+    fi
+}
+
+flush_rules()
+{
+    TABLES=$(ip6tables-save | sed -E -n 's/^\*//p')
+    for table in $TABLES
+    do
+        CHAINS=$(ip6tables-save -t $table | sed -E -n 's/^:([A-Z]+).*/\1/p')
+        for chain in $CHAINS
+        do
+            # policy can't be set on user-defined chains
+            ip6tables -t $table -P $chain ACCEPT || true
+        done
+        ip6tables -t $table -F
+        ip6tables -t $table -Z
+        ip6tables -t $table -X
+    done
+}
+
+case "$1" in
+start|restart|reload|force-reload)
+    load_rules
+    ;;
+save)
+    save_rules
+    ;;
+stop)
+    # Why? because if stop is used, the firewall gets flushed for a variable
+    # amount of time during package upgrades, leaving the machine vulnerable
+    # It's also not always desirable to flush during purge
+    echo "Automatic flushing disabled, use \"flush\" instead of \"stop\""
+    ;;
+flush)
+    flush_rules
+    ;;
+*)
+    echo "Usage: $0 {start|restart|reload|force-reload|save|flush}" >&2
+    exit 1
+    ;;
+esac

configs/LinuxB/99-sysctl.conf

@@ -0,0 +1,68 @@
+#
+# /etc/sysctl.conf - Configuration file for setting system variables
+# See /etc/sysctl.d/ for additional system variables.
+# See sysctl.conf (5) for information.
+#
+
+#kernel.domainname = example.com
+
+# Uncomment the following to stop low-level messages on console
+#kernel.printk = 3 4 1 3
+
+##############################################################3
+# Functions previously found in netbase
+#
+
+# Uncomment the next two lines to enable Spoof protection (reverse-path filter)
+# Turn on Source Address Verification in all interfaces to
+# prevent some spoofing attacks
+#net.ipv4.conf.default.rp_filter=1
+#net.ipv4.conf.all.rp_filter=1
+
+# Uncomment the next line to enable TCP/IP SYN cookies
+# See http://lwn.net/Articles/277146/
+# Note: This may impact IPv6 TCP sessions too
+#net.ipv4.tcp_syncookies=1
+
+# Uncomment the next line to enable packet forwarding for IPv4
+net.ipv4.ip_forward=1
+
+# Uncomment the next line to enable packet forwarding for IPv6
+#  Enabling this option disables Stateless Address Autoconfiguration
+#  based on Router Advertisements for this host
+#net.ipv6.conf.all.forwarding=1
+
+
+###################################################################
+# Additional settings - these settings can improve the network
+# security of the host and prevent against some network attacks
+# including spoofing attacks and man in the middle attacks through
+# redirection. Some network environments, however, require that these
+# settings are disabled so review and enable them as needed.
+#
+# Do not accept ICMP redirects (prevent MITM attacks)
+#net.ipv4.conf.all.accept_redirects = 0
+#net.ipv6.conf.all.accept_redirects = 0
+# _or_
+# Accept ICMP redirects only for gateways listed in our default
+# gateway list (enabled by default)
+# net.ipv4.conf.all.secure_redirects = 1
+#
+# Do not send ICMP redirects (we are not a router)
+#net.ipv4.conf.all.send_redirects = 0
+#
+# Do not accept IP source route packets (we are not a router)
+#net.ipv4.conf.all.accept_source_route = 0
+#net.ipv6.conf.all.accept_source_route = 0
+#
+# Log Martian Packets
+#net.ipv4.conf.all.log_martians = 1
+#
+
+###################################################################
+# Magic system request Key
+# 0=disable, 1=enable all, >1 bitmask of sysrq functions
+# See https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html
+# for what other values do
+#kernel.sysrq=438
+

configs/LinuxC/00-installer-config.yaml

@@ -0,0 +1,10 @@
+# This is the network config written by 'subiquity'
+network:
+  ethernets:
+    enp0s3:
+      dhcp4: true
+    enp0s8:
+      dhcp4: no
+      addresses: [192.168.3.100/24]
+      gateway4: 192.168.3.1
+  version: 2