# Baris Kaan Yuksel > IT System and Network Specialist ## Posts - [IP DHCP Snooping configuration](https://barisyuksel.com.tr/2026/04/19/ip-dhcp-snooping-configuration/): What is IP DHCP snooping? Think of it as a security guard for your network’s IP address assignment process. In a normal setup, a client asks for an IP and a server gives it one, but without snooping, your switch is “blind”—it doesn’t know if that DHCP response came from your actual server or a […] - [Router On A Stick Method for Layer 2 switches (ROAS Inter-vlan Legacy Communication) CISCO](https://barisyuksel.com.tr/2025/11/24/router-on-a-stick-method-for-layer-2-switches-roas-inter-vlan-legacy-communication-cisco/): In this lab, we will inspect how intervlan communication handled on Layer-3 Router with Router On a Stick model. If you have layer 2 switches for end devices, then you will need a layer 3 router or switch for intervlan communication. Layer 2 devices cannot do IP routing between VLAN gateways (SVIs) so therefore you […] - [LACP (802.3ad) connection between Cisco Switch and Fortigate Firewall](https://barisyuksel.com.tr/2025/07/09/lacp-802-3ad-connection-between-cisco-switch-and-fortigate-firewall/): LACP (Link Aggregation Control Protocol) is part of the IEEE 802.3ad standard that allows multiple physical Ethernet links to be combined into a single logical link, called a link aggregation group (LAG) or EtherChannel (in Cisco terms). Why do we need LACP? Increased Bandwidth: Combine several links for higher throughput. Redundancy: If one link fails, […] - [DHCP Failover configuration for VLANs](https://barisyuksel.com.tr/2025/06/07/dhcp-failover-configuration-for-vlans/): In this lab, we will simulate 2 different DHCP server on the same network for failover backup. Our primary DHCP server is 192.168.30.100 and secondary DHCP server is 192.168.100.100 . We have 4 VLANs; VLAN 10 and VLAN 20 are used for end users. VLAN 30 and VLAN 100 are used for system and network […] - [Port Isolation on VLAN subnets](https://barisyuksel.com.tr/2025/03/02/port-isolation-on-vlan-subnets/): This feature can be used to isolate devices in the same VLAN from each other while allowing them to access external resources (e.g., the internet, a router, or a server). It is often used in guest networks or environments where you don’t want devices in the same VLAN to communicate directly with each other. How […] - [Difference between 2.4 Ghz and 5 Ghz frequency bands on Wifi communication](https://barisyuksel.com.tr/2025/03/01/difference-between-2-4-ghz-and-5-ghz-frequency-bands-on-wifi-communication/): The 2.4 GHz and 5 GHz wireless networks are wireless communications wireless networks. Each is distinct in advantage and disadvantage depending on application. Feature 2.4 GHz 5 GHz Speed Slower (max ~600 Mbps, depending on Wi-Fi standard) Faster (up to several Gbps, depending on Wi-Fi standard) Range Longer range (penetrates walls and obstacles better) Shorter range (weaker penetration through walls) Interference More interference (crowded band with Bluetooth, microwaves, etc.) […] - [Active Directory Installation on Windows Server 2019 [Step-by-step]](https://barisyuksel.com.tr/2025/01/28/active-directory-installation-on-windows-server-2019-step-by-step/): In this lab, we will install Active Directory role on Windows Server Data Center 2019 server. We will start with the basics, like installing the OS first then will continue to configure initial steps like setting IP address, disabling firewall and other things. This lab consists of 27 screenshots with explanations so follow all the […] - [Mission Critical Systems L3 Core Switch HA](https://barisyuksel.com.tr/2025/01/12/mission-critical-systems-l3-core-switch-ha/): In this lab, we will use HSRP protocol to create high availability for our topology using two core switches as primary and secondary (backup) in case of a failure. By this way, we will avoid single point of failure and eliminate the system downtime. HSRP (Hot Standby Router Protocol) is a redundancy protocol developed by […] - [Creating VLANs on Fortigate and Cisco Core L3 switch connection](https://barisyuksel.com.tr/2024/11/02/creating-vlans-on-fortigate-and-cisco-core-l3-switch-connection/): In this lab, I will show you how to create VLANs on Fortigate firewall instead of creating VLANs on Cisco L3 switch. You can also find the Cisco to Fortigate version in my posts. We will create 3 vlans as VLAN 10 – 192.168.10.1/24 , VLAN 20 – 192.168.20.1/24 , VLAN 30 – 192.168.30.1/24 and […] - [Syslog Integration With Fortigate Firewall](https://barisyuksel.com.tr/2024/10/05/syslog-integration-with-fortigate-firewall/): In this lab, we will configure Windows OS based Kiwi Syslog with Fortigate firewall. There are already some enterprise level solutions from Fortigate but this lab is prepared for those who wants to keep their external syslog server on Windows server. There are several syslog application, in this example we choose Kiwi syslog. Also you […] - [[Hacking Series/Lab 5] –How to use CAM table overflow for attack? (MAC flooding)](https://barisyuksel.com.tr/2024/08/09/hacking-series-lab-5-how-to-use-cam-table-overflow-for-attack-mac-flooding/): Disclaimer: These methods and techniques are purely for educational and informational purposes. All attacks were carried out in an offline isolated virtual environment. The use of these techniques in normal life is illegal and the responsibility lies strictly with the reader. DO NOT USE THESE TECHNIQUES IN REAL LIFE ! A CAM table attack, also […] - [[Hacking Series/Lab 4] –How to launch MAN IN THE MIDDLE Attack? (ARP poisoning)](https://barisyuksel.com.tr/2024/08/03/hacking-series-lab-4-how-to-launch-man-in-the-middle-attack-arp-poisoning/): Disclaimer: These methods and techniques are purely for educational and informational purposes. All attacks were carried out in an offline isolated virtual environment. The use of these techniques in normal life is illegal and the responsibility lies strictly with the reader. DO NOT USE THESE TECHNIQUES IN REAL LIFE ! ARP poisoning and Man-in-the-Middle (MITM) […] - [[Hacking Series/Lab 3] –How to launch CDP (LLDP) Attack to a Cisco switch?](https://barisyuksel.com.tr/2024/08/01/hacking-series-lab-3-how-to-launch-cdp-lldp-attack-to-a-cisco-switch/): Disclaimer: These methods and techniques are purely for educational and informational purposes. All attacks were carried out in an offline isolated virtual environment. The use of these techniques in normal life is illegal and the responsibility lies strictly with the reader. DO NOT USE THESE TECHNIQUES IN REAL LIFE ! CDP Attack (Cisco Discovery Protocol) […] - [[Hacking Series/Lab 2] – SNMP Attack ! This training was created for preventive defensive purposes.](https://barisyuksel.com.tr/2024/07/29/hacking-series-lab-2-snmp-attack-this-training-was-created-for-preventive-defensive-purposes/): Disclaimer: These methods and techniques are purely for educational and informational purposes. All attacks were carried out in an offline isolated virtual environment. The use of these techniques in normal life is illegal and the responsibility lies strictly with the reader. DO NOT USE THESE TECHNIQUES IN REAL LIFE ! An SNMP (Simple Network Management […] - [[Hacking Series/Lab 1] - VLAN Hopping Attack ! This training was created for preventive defensive purposes.](https://barisyuksel.com.tr/2024/07/28/hacking-series-training-1-vlan-hopping-attack-this-training-was-created-for-preventive-defensive-purposes/): Disclaimer: These methods and techniques are purely for educational and informational purposes. All attacks were carried out in an offline isolated virtual environment. The use of these techniques in normal life is illegal and the responsibility lies strictly with the reader. DO NOT USE THESE TECHNIQUES IN REAL LIFE ! In this training, I will […] - [OT/IT Security - Internal Firewall Fortigate Implementation with configurations for your critical networks](https://barisyuksel.com.tr/2024/07/14/ot-it-security-internal-firewall-fortigate-implementation-with-configurations-for-your-critical-networks/): An internal firewall, also known as an internal network firewall or a segment firewall, is a security system designed to protect and control traffic between different segments within an organization’s internal network. Unlike a perimeter firewall, which protects the network from external threats, an internal firewall focuses on securing the internal network by regulating the […] - [How to create DMZ (Demilitarized Zone) on Fortigate Firewall?](https://barisyuksel.com.tr/2024/05/19/how-to-create-dmz-demilitarized-zone-on-fortigate-firewall/): What is DMZ (Demilitarized Zone)? A DMZ (Demilitarized Zone) in computer networking refers to a physical or logical subnetwork that contains and exposes an organization’s external-facing services to an untrusted network, usually the internet. The purpose of a DMZ is to add an additional layer of security to an organization’s local area network (LAN); an […] - [GRE Tunnels between multiple sites](https://barisyuksel.com.tr/2024/05/01/gre-tunnels-between-multiple-sites/): A GRE (Generic Routing Encapsulation) tunnel in Cisco is a method of encapsulating and tunneling network traffic over an IP network. It allows the creation of a virtual point-to-point link between two endpoints, typically routers or switches, across an existing network infrastructure. Here’s how it works: GRE tunnels are often used for various purposes, such […] - [Multiple company-sites IPSEC connection with multiple VLANs](https://barisyuksel.com.tr/2024/02/25/multiple-company-sites-ipsec-connection-with-multiple-vlans/): IPsec, short for Internet Protocol Security, is a suite of protocols used to ensure secure communication over IP networks. It provides security services at the IP layer by enabling encryption, authentication, and integrity checking of IP packets. IPsec can be used to establish secure VPN (Virtual Private Network) connections between remote networks or individual devices, […] - [Ethernet MAC Port-security](https://barisyuksel.com.tr/2024/02/08/ethernet-mac-port-security/): Today we will implement port security on our Cisco switch. We will bind the MAC address of the NIC device with our related port. So if some changes happen on the physical ports, then new device will be restricted. CISCO SWITCH MAIN CONFIGURATION Switch>enable Switch#configure terminal Enter configuration commands, one per line. End with CNTL/Z. […] - [PfSense firewall + L3 Core switch configuration with VLANs](https://barisyuksel.com.tr/2023/12/28/pfsense-firewall-l3-core-switch-configuration-with-vlans/): In this lab, we will create 3 vlans and connect our core switch to pfSense firewall with a transit network. Then we will configure our firewall with these vlan subnets. LAN related traffic will not hit the firewall, because SVIs (VLANgateways) will be created on L3 Core switch. All the necessary permissions between vlans will […] - [Multiple DHCP Server Configurations For VLANs](https://barisyuksel.com.tr/2023/12/11/multiple-dhcp-server-configurations-for-vlans/): On this practice lab, we will configure two DHCP servers for 4 different VLANs. We will create the VLANs on the core switch, then we will assign the DHCP servers to VLANs with the command of “ip helper-address“. By this method, you will be able to use different DHCP servers for different purposes. Cisco Core […] - [Cisco ASA Transparent Internal Firewall Configuration](https://barisyuksel.com.tr/2023/10/27/cisco-asa-transparent-internal-firewall-configuration/): Cisco ASA (Adaptive Security Appliance) is a security device that provides firewall, VPN, and other security services for networks. It can operate in multiple modes, including Routed Mode and Transparent Mode. Let’s focus on Cisco ASA Transparent Mode. In Transparent Mode, the Cisco ASA firewall is inserted into a network without requiring any IP address […] - [Fortinet Firewall - Multiple WAN ISP Basic Failover](https://barisyuksel.com.tr/2023/10/15/fortinet-firewall-multiple-wan-isp-basic-failover/): On our topology, we have Fortigate firewall, Cisco routers and 2 ISP provider with 20.0.0.2 and 10.0.0.2 gateways. We would like to setup a basic failover on Fortigate firewall which will allow us to use 2nd ISP link if ISP-1 drops. Basic idea behind this is “administrative distance” on Static routes on the firewall. We […] - [Forgot your Cisco Router Password? Follow these easy steps for recovery on terminal](https://barisyuksel.com.tr/2023/10/01/forgot-your-cisco-router-password-follow-these-easy-steps-for-recovery-on-terminal/): What is Cisco Rommon Mode? ROM Monitor Mode, often referred to as “ROMMON” mode, is a low-level mode on Cisco networking devices that allows for basic device recovery and maintenance operations. ROMMON stands for “ROM Monitor,” and it provides a way to interact with the device’s firmware and bootstrap loader when normal operating conditions or […] - [What is Netflow protocol? Deployment of Netflow server](https://barisyuksel.com.tr/2023/09/17/what-is-netflow-protocol-deployment-of-netflow-server/): NetFlow is a network protocol developed by Cisco that is used for network traffic monitoring and analysis. It allows network administrators to collect and view information about the traffic flowing through their network devices, such as routers and switches. A NetFlow server, sometimes referred to as a NetFlow collector or analyzer, is a system or […] - [What is RIP Protocol in networking? How implement RIP on routers?](https://barisyuksel.com.tr/2023/09/03/what-is-rip-protocol-in-networking-how-implement-rip-on-routers/): RIP, which stands for Routing Information Protocol, is a distance-vector routing protocol used in computer networking and particularly in Cisco networking equipment. RIP is one of the oldest and simplest routing protocols used to exchange routing information between routers in a network. Cisco routers can be configured to use RIP for routing purposes. Here are […] - [What is a DNS Server? How to setup on a network?](https://barisyuksel.com.tr/2023/08/27/what-is-a-dns-server-how-to-setup-on-a-network/): A DNS server, or Domain Name System server, is a crucial component of the internet infrastructure that helps translate human-readable domain names into IP addresses. Domain names are the familiar web addresses that people use to access websites, such as “www.barisyuksel.com.tr“. IP addresses, on the other hand, are numeric identifiers that computers and devices use […] - [Syslog Server implementation for Cisco network devices](https://barisyuksel.com.tr/2023/08/09/syslog-server-implementation-for-cisco-network-devices/): On Cisco networking devices, a syslog server refers to a system or application that collects, stores, and manages log messages generated by the Cisco devices. These log messages contain valuable information about the operation, performance, and events occurring on the network equipment. The syslog server helps network administrators and engineers to monitor, troubleshoot, and analyze […] - [What is HSRP protocol? How to implement on the network?](https://barisyuksel.com.tr/2023/08/01/what-is-hsrp-protocol-how-to-implement-on-the-network/): HSRP, or the Hot Standby Router Protocol, is a Cisco proprietary protocol that enables two or more routers to work together in a group to present the illusion of a single virtual router to hosts on a LAN. The main purpose of HSRP is to establish network redundancy and avoid single points of failure, thus […] - [What is EIGRP Protocol? How to use EIGRP?](https://barisyuksel.com.tr/2023/07/23/what-is-eigrp-protocol-how-to-use-eigrp/): EIGRP, which stands for Enhanced Interior Gateway Routing Protocol, is a dynamic routing protocol used in computer networks to help routers exchange routing information efficiently. It was developed by Cisco Systems and is primarily designed for use in IP networks, including both local area networks (LANs) and wide area networks (WANs). EIGRP is an advanced […] - [Fortigate Firewall HA (High availability) Deployment](https://barisyuksel.com.tr/2023/05/21/fortigate-firewall-ha-high-availability-deployment/): Deploying high availability (HA) on Fortinet FortiGate firewalls offers several benefits, including: On this topology we have two Fortinet Fortigate firewalls, two network switches, one router, four end-users. We will complete all the physical connections between devices, then jump into Fortigate configurations. We will start configuring Master Firewall with 3 interfaces, LAN-WAN-HA LINK. Second firewall […] - [Cisco ASA 5506 firewall initial deployment with CLI](https://barisyuksel.com.tr/2023/05/19/cisco-asa-5506-firewall-initial-deployment-with-cli/): Cisco ASA (Adaptive Security Appliance) is a firewall and network security device produced by Cisco Systems. It provides advanced firewall, VPN (Virtual Private Network), and intrusion prevention capabilities to protect networks from unauthorized access, threats, and attacks. The Cisco ASA firewall offers both hardware and software components, including a dedicated security operating system called Cisco […] - [What is a network port? Well known ports and registered ports.](https://barisyuksel.com.tr/2023/05/16/what-is-a-network-port-well-known-ports-and-registered-ports/): A network port is a communication endpoint in a network. It is identified by a numerical value, called a port number, which helps direct network traffic to specific applications or services running on a device. Ports allow multiple applications to coexist on the same network device by assigning unique port numbers to each application. There […] - [Cisco WLAN Controller with VLANs through multiple SSIDs](https://barisyuksel.com.tr/2023/05/04/cisco-wlan-controller-with-vlans-through-multiple-ssids/): Let’s start configuring our VLANs and ports. We will create 3 VLANs on SW1 core switch. One of them will serve as Management subnet, others will serve as Office and Guest networks. Upon completion of VLAN and port configurations, we will start configuring Cisco Wireless Controllers and our Cisco Access Points. Both access points will […] - [What is Etherchannel ? How to use it?](https://barisyuksel.com.tr/2023/04/26/what-is-etherchannel-how-to-use-it/): EtherChannel is a technology used in networking to create a logical link aggregation or link bundling of multiple physical Ethernet links into a single logical link, providing increased bandwidth, improved redundancy, and load balancing across the bundled links. It is also known as Link Aggregation, Port Channel, or Port Aggregation. EtherChannel is typically used in […] - [Cisco ASA Firewall deployment via Cisco L3 Switch with VLANs.](https://barisyuksel.com.tr/2023/04/22/cisco-asa-firewall-deployment-via-cisco-l3-switch-with-vlans/): In this post, we will be talking about the Cisco firewall installation and integration with VLANs installed Cisco Core L3 switch. I know, probably most of you had some troubles while you were implementing this topology 🙂 I would like to share all the details that I configured on real devices. What do we need […] - [How to create VLANs on Huawei switches?](https://barisyuksel.com.tr/2023/04/07/how-to-create-vlans-on-huawei-switches/): Huawei switches are network switches developed and produced by Huawei Technologies Co. Ltd., a leading global provider of information and communications technology (ICT) infrastructure and smart devices. Huawei switches offer a wide range of features and functionalities for both small and large-scale enterprise networks, including but not limited to: Huawei switches offer a robust and […] - [Cisco IOS and running-config backup to TFTP server](https://barisyuksel.com.tr/2023/03/30/cisco-ios-and-running-config-backup-to-tftp-server/): Backing up the Cisco IOS and running-config is extremely important for several reasons: To summarize, backing up the Cisco IOS and running-config is critical for ensuring network availability, performance, and security. It is a best practice that all network administrators should follow to avoid potential issues and minimize downtime. First create your TFTP server on […] - [What is OSPF Protocol? How to implement it on enterprise networks?](https://barisyuksel.com.tr/2023/03/22/what-is-ospf-protocol-how-to-implement-it-on-enterprise-networks/): OSPF (Open Shortest Path First) is a routing protocol used in computer networks to exchange routing information among routers. It is an Interior Gateway Protocol (IGP) and is commonly used in large enterprise networks and service provider networks. OSPF works by having routers send link-state advertisements (LSAs) to all other routers in the network. These […] - [What is NTP (Network Time Protocol) ? How to configure it on Cisco switches/routers?](https://barisyuksel.com.tr/2023/02/25/what-is-ntp-network-time-protocol-how-to-configure-it-on-cisco-switches-routers/): Network Time Protocol (NTP) is a protocol used to synchronize the time on computers and other network devices. It works by sending messages between computers to determine the exact time and date. NTP is an important part of any computer network, as it ensures that all devices have the same time and date. This makes […] - [Cisco switch/router SSH configuration](https://barisyuksel.com.tr/2023/02/12/cisco-switch-router-ssh-configuration/): Configuring a Cisco switch for SSH connection is an important task for network administrators. This process requires a good understanding of the Windows OS and network protocols such as TCP/IP, traceroute, etc. In this article, we will discuss the steps to configure a Cisco switch for SSH connection and how to troubleshoot any issues that […] - [What is "traceroute" command? How does it work on Windows OS?](https://barisyuksel.com.tr/2023/02/05/what-is-traceroute-command-how-does-it-work-on-windows-os/): The traceroute command is a network troubleshooting tool used to trace the path of data packets from one host to another. It works by sending out a series of TCP/IP packets with increasing Time-To-Live (TTL) values. As each packet passes through switches and routers, the TTL value is decremented until it reaches 0, at which […] - [How to create IPSEC VPN Tunnels on Fortigate firewalls between the sites?](https://barisyuksel.com.tr/2023/02/01/how-to-create-ipsec-vpn-tunnels-on-fortigate-firewalls-between-the-sites/): Setting up an IPSEC VPN tunnel between two sites is a great way to securely connect them. It allows for secure communication between the two sites and helps protect data from being intercepted. IPSEC VPN tunnels on Fortigate firewalls are easy to setup and configure, and can be done with the help of Cisco or […] - [How to setup Fortigate firewall with Cisco core switches configured with VLANs?](https://barisyuksel.com.tr/2023/01/31/how-to-setup-fortigate-firewall-with-cisco-core-switches-configured-with-vlans/): Configuring a Fortigate Firewall is an important step for any network administrator. It not only ensures that the firewall is set up correctly, but also helps keep the network secure from any potential threats. In this article, we will discuss how to configure a Fortigate Firewall using CLI, from its first setup to more advanced […] - [What is dynamic routing in Cisco? How to create dynamic routing on router devices?](https://barisyuksel.com.tr/2023/01/24/what-is-dynamic-routing-in-cisco-how-to-create-dynamic-routing-on-router-devices/): Dynamic routing is a feature of Cisco routers that allows them to adjust routing paths based on changes in the network environment. It allows for more efficient use of router resources and helps ensure that traffic is routed optimally. With dynamic routing, router devices can automatically select the best route for data packets to reach […] - [What is Spanning Tree Protocol? How to implement STP on multiple switch or router environment? How many STP modes are there?](https://barisyuksel.com.tr/2023/01/22/what-is-spanning-tree-protocol-how-to-implement-stp-on-multiple-switch-or-router-environment-how-many-stp-modes-are-there/): Spanning Tree Protocol (STP) is a Layer 2 protocol used to prevent loops in the network by creating a logical topology of the network. It is used in Cisco IOS devices such as switches and routers to ensure redundant links are not creating broadcast storms and loops. STP works by assigning each switch or router […] - [Initial/Basic configuration of Cisco Switches](https://barisyuksel.com.tr/2023/01/17/initial-basic-configuration-of-cisco-switches/): Configuring Cisco switches is an essential part of any IT network. With the right configuration, you can ensure that your network is running optimally and securely. In this article, we will discuss how to configure a Cisco switch using the Cisco IOS command-line interface (CLI). We will cover topics such as setting up basic networking […] - [What is ARP protocol? How to use arp commands on Windows?](https://barisyuksel.com.tr/2023/01/12/what-is-arp-protocol-how-to-use-arp-commands-on-windows/): The Address Resolution Protocol (ARP) is an essential protocol used in computer networks. It allows computers to map IP addresses to physical addresses like Ethernet MAC addresses, allowing them to communicate over the network. The arp command is a Microsoft Windows-based command line utility that can be used to view and modify the ARP cache. […] - [What is Voice VLAN? How to use IP Phones on our network?](https://barisyuksel.com.tr/2022/12/24/what-is-voice-vlan-how-to-use-ip-phones-on-our-network/): Voice VLAN is used to provide voice traffic with a dedicated VLAN. Voice traffic is isolated from other network traffic and so it doesn’t slow down the network. In order to make a work voice vlan and computer together, you should turn on the voice vlan in your cisco phone. This is done by providing […] - [What is VTP (VLAN Trunking Protocol) ?](https://barisyuksel.com.tr/2022/12/20/what-is-vtp-vlan-trunking-protocol/): A VTP server is a switch to which other switches are connected. The VTP server maintains the VLAN database and propagates it to all the other switches. There are three modes in which a VTP server can operate: Server, Client and Transparent. The Server mode is used when there is more than one switch in […] - [How to create Vmware server 6.5?](https://barisyuksel.com.tr/2022/11/07/how-to-create-vmware-server-6-5/): VMware server is a virtualization software that helps to create and manage virtual machines. This article will show you how to install VMware server 6.5 on Windows 10. Install VMware Server 6.5 1) Download VMware Server from the official website 2) Install the software on your computer 3) Open the program and select “Create a […] - [Extended ACL list for enterprise network system. Download](https://barisyuksel.com.tr/2022/11/05/extended-acl-list-enterprise-network-system-full-simulation-on-cisco-package-tracer-download/): In this simulation you can find all necessary configuration. You can download .pkt Cisco Package Tracer file and open it on your computer. There are 5 VLAN configured and 1 extended ACL implemented on whole VLANs. Basically, hit CLI tab on the switch which you want to check then enter “show running-configuration” command to see […] - [Inter-VLAN Communication (Routing) and Extended ACL](https://barisyuksel.com.tr/2022/11/02/intervlan-routing-and-extended-acl/): Hello everyone, In this example we will create 4 VLANs on a mid-level network infrastructure. Above you can see the logical topology which we created. There is one DHCP server on 192.168.4.10/24 , one SQL-server on 192.168.3.2, four different client hosts and two layer-3 switches. We will use EXTENDED ACL to create some rules on […] - [What is trunk port? How to use them on switches?](https://barisyuksel.com.tr/2022/10/11/what-is-trunk-port-how-to-use-them-on-switches/): In this example, we will use 2 different switches, 2 different VLANs (VLAN 10 and VLAN 20). On each switches there will be a “trunk port” to carry all VLAN related data through 802.1Q protocol. Trunk ports are capable of carrying multiple VLAN data through the network. First, we will use 4 clients which are […] - [10 Most Used Commands on Cisco OS](https://barisyuksel.com.tr/2022/10/10/10-most-used-commands-on-cisco-os/): #enable This command enables users to enter their commands on the terminal. Moves user to privilege mode. #configure terminal This command allows users to make some changes on the configuration. #show running-configuration This command shows you the latest running configuration on the device. To not to lose your latest configurations which you have done, you […] - [Routing between networks / Cisco router configuration](https://barisyuksel.com.tr/2022/10/10/routing-between-networks-cisco-router-configuration/): HOW TO ROUTE NETWORKS USING CISCO ROUTERS ? In this example topology, we have 3 different networks. We have 192.168.1.0 network on the left side, 192.168.2.0 on the right side. Also 3rd network is between routers on 192.168.0.0 networks. So we will configure our topology as above. First let’s start with clients; give IP addresses […] - [DHCP server configuration on Cisco switch](https://barisyuksel.com.tr/2022/10/10/dhcp-server-configuration-on-cisco-switch/): How to configure DHCP service on Cisco Layer 3 switch? Let’s assume that we have an imaginary network called CORPORATE. This network is 192.168.1.0 and the subnet mask is 255.255.255.0 (/24). At this example, we have 3 client notebook which get IP address from our internal DHCP server which is configured in Cisco switch. First […] - [Basic VLAN Configuration on Cisco switches](https://barisyuksel.com.tr/2022/10/08/basic-vlan-configuration/): Here you can find the logical topology which was created on Cisco package tracer. There are 3 different VLANs on this system. VLAN 10 is highlighted green, VLAN 2O is highlighted orange and VLAN 30 is used for server management. On this network topology, we have 4 clients, 1 layer-3 switch and 1 DHCP server […] ## Pages - [Contact](https://barisyuksel.com.tr/contact/): Please feel free to contact me for your inquires. Happy networking 🙂 E-mail : info@barisyuksel.com.tr - [About Me](https://barisyuksel.com.tr/about-me/): Hi, I’m Baris Kaan Yuksel. IT System Administrator currently based in 📍 Stuttgart-Germany. I am specialized in System and Network Management. Graduated from Ahmet Yesevi University in the field of Master of science in Management Information Systems with high honor degree 3.9/4.0 grade. My master graduation project was about : “Network segmentation with VLAN technology […] ## Optional - [Agent (MCP protocol)](websites-agents.hostinger.com/barisyuksel.com.tr/mcp) [comment]: # (Generated by Hostinger Tools Plugin)