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Network Basic

Grasp the network flow

Must Know As a Network Engineer

Ethernet

IP

TCP/UDP

Switching

Routing

NAT

Firewall

TLS (former SSL)

Link Aggregation

First Hop Redundancy

ACL

PPP/PPPoE

Spanning Tree Protocol(STP)

Network Advanced

NW Security

OSPF

Multicast

MPLS-VPN

Ethernet OAM

Shortest Path Bridging(SPB)

Server Basic

Server Architecture

Windows Basic Knowledge

Linux Basic Knowledge

Virtual-Technology Basic

NW System Monitor

Design for Backup

Design for UPS & Power

Server Advanced

Digital Certificate

Appliance Server

Server Software

L7 Protocol

syslog

SNMP

NTP

DNS

SMTP

LDAP

Radius

Product Specific

FortiGate

DELL Server

HP Server

HP switch (H3C, 3COM)

PaloAlto

Can be used in field

Troubleshoot

Script

Uncategorized

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About xfsaild related errors

What is xfsaild? xfsaild stands for XFS...

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Overview of HP stack stack technology IRF (Intelligent Resilient Framework) and setting

What is the HP Switch IRF? The techniqu...

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Mechanism of outgoing e-mail address impersonation [Mailsploit] ~ Basic e-mail anti-spoof technology SMTP AUTH, DKIM, SPF / SenderID overview (merit · demerit) Commentary and relation with this attack-

What is Mailsploit? Mailsploit is an at...

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Ping results – Difference between “Request timed out” and “Destination Host Unreachable”, General Failure –

In case Ping is success. When Ping is s...

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How does WPA2’s vulnerability [KRACK] allow wireless frames decrypted specifically? Where is the vulnerability of the protocol itself?

Logic that can be decrypted with KRACK ...

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Man in the Middle attack (Channel-based MitM) in Wireless LAN

Man in the Middle attack of Wi-Fi The v...

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[TCP ZeroWindow], [TCP Window Update], [TCP Window Full] displayed on Wireshark – cause & countermeasure

I summarized the display related to "TCP...

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HP switch config initialization

HP switch config initialization Execute...

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HP switch firmware update method (HP 5130 example)

Download firmware from HP website The H...

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What you can do with built-in group “BackupOperators privilege”, differences from administrators authority

What is the Built-in Group? A Built-in ...

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Essential differences between [Specter] & [Meltdown] and basic knowledge for understanding

Introduction In this article "process" ...

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How do CPU vulnerabilities [Spectre], [Meltdown] work specifically? What is the influence range?

Overview and scope of influence of Spect...

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How transparent proxy works with http and https

What is a transparent proxy? Transparen...

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The way of importing Digital Certificate to the HP switch HP5130

For the implementation of the Web authen...

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Web Login Load Test Tool “Curl-Loader”

J-Meter, etc. is famous as the Web of th...

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About tracert (traceroute)

tracert (traceroute) is a tool to verify...

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What is Virtual Memory? ~ About swap, MMU, paging table ~

What is Virtual Memory? The word virtua...

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About Call Trace

The Call Trace, is a stack trace of ...

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“Bad TCP” Error in Wireshark

We summarize the meanings and causes of ...

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Multicast stops halfway, switches to unicasts

Cause Host sending multicast and host r...

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About VRF (Virtual Routing and Forwarding)

About VRF VRF stands for Virtual Routin...

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Policy-Based-Routing and IPROUTE2

PBR (Policy-Based Routing) I wrote befo...

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Configuration of MPLS-VPN (Super Backbone and Sham-Link)

I will introduce of the example of confi...

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MPLS-VPN (MP-BGP) Details

MP-BGP Route information in can be tran...

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MPLS-VPN Overview

The router of the description in the bas...

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MPLS basic#5 TTL Propagation

The TTL Propagation, when transferring M...

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MPLS basic#4 PHP (Penultimate Hop Popping)

PHP The PHP and stands for Penultimate ...

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MPLS basic#3 FIB table / LFIB table

FIB table In border router between MPLS...

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MPLS basic#2 label exchange and LIB table

In front of the label exchange, by each ...

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MPLS basic#1 LDP Behavior

MPLS network needs to exchange not only ...

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About MPLS

MPLS (Multi-Protocol Label Switching) is...

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What is Ethernet OAM?

What is OAM? OAM stands for Operations,...

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About Digital Certificate

Digital Certificate is tool which realiz...

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How to determine Active port / Standby port by LACP

In LACP, up to 16 Ethernet can be includ...

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LACP format and structure

Format of LACP The format of LACP is as...

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What is Slow Protocol

When link aggregation and LACP are s...

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Right condition for exchange the router by OSPF

Right condition for exchange the router ...

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Features of multi-access topology

In multi-access topologies such as b...

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Condition of OSPF neighbor establishment (2WAY)

What is 2WAY OSPF routers in the same s...

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OSI Reference Model and IP Set Model

What is OSI Reference Model and IP Set M...

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UTM Overview and Necessity

What is UTM The firewall is an applianc...

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How Stateful Inspection Works

What is Stateful Inspection Stateful In...

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Format of UDP

As mentioned before, UDPis light in load...

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TCP flow control and congestion control

As mentioned before, since it is ineffic...

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Reliability of TCP

TCP reliability is implemented with sequ...

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TCP state transition

TCP has an attribute called " State ...

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TCP connection

The TCP connection starts with 3 way han...

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TCP Options

TCP options is represented as following ...

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TCP segment format

The communication data unit of TCP is of...

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TCP / UDP Overview

TCP/UDP provides a communication channel...

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What is ICMP ~ Difference from layer and TCP, about how to use ~

What is ICMP ICMP stands for Internet C...

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What is IPアドレス

IP address is the address on network...

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Palo Alto CaptivePortal Authentication Exclusion

In PaloAlto, consider the case for a cer...

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Palo Alto CaptivePortal – Detail Behavior and Design Guide –

CaptivePortal of PaloAlto You can be ma...

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PaloAlto Dependencies of Application Identification

PaloAlto Dependencies of Application Ide...

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Broadcast routing

There are two types of IP broadcast. ...

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Cause and avoidance design of routing loop

The routing loop is said the state that ...

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Routing of the terminal

Although we've seen how the router forwa...

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Rule of routing #5 Recursive Routing

NextHop address of the routing is ba...

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Rule of routing #4 Administrative Distance (AD)

About Administrative Distance (AD) Admi...

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Rule of routing #3 Longest Match

Consider the network such as the fol...

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Rule of routing #2 Packet Discarding

(In Layer 3, ) the cases that incomming ...

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Rule of routing #1 Header rewriting

There was no particular change in th...

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Routing table

In the memory of the NW devices of Layer...

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Configuring Routing

Although switching can learn the MAC add...

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Routing Overview

The Layer 2 defines communication direct...

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Difference between MAC address table and ARP table

The difference between the MAC address t...

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Tshark

Executing packet capture in Wireshark, i...

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Differrence between MTU & MSS, IP Fragmentation & TCP Segmentation

Difference between MTU & MSS MTU(...

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The flow of IP communication – the example of HTTP –

Let's have a look up the series of IP co...

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The flow of IP communication – Inner segment / Inter-segment –

Today's IP communication is based onEthe...

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How does the Internet work?

Internet is interacting with a computer ...