Author Archives: pankajsheoran

FreeBSD commands

The purpose of this post is to provide useful command needed while working on freebsd: How to check ipv4 routing table: netstat -rn -4 How to install a package: pkg install apache24 How to get list of software installed in … Continue reading

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Understanding HTTP methods

HTTP connect method: One of the HTTP request is CONNECT method.  When you have a client with explicit proxy configured at that time when the client tries to connect to some https website then the client send a HTTP CONNECT … Continue reading

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Squid Proxy basics

How to start squid proxy in ubuntu? service squid start How to restart squid proxy in ubuntu? service squid restart Where the configuration file for squid proxy is stored. The squid proxy configuration file “squid.conf” you will find in “/etc/squid/” … Continue reading

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Resolving ASA 8.4 NAT mystery

Static NAT/PAT: object network dynamic-nat-ip host 12.12.12.16 object network R3 host 13.13.13.13 nat (dmz,outside) static dynamic-nat-ip service tcp telnet ftp For traffic from dmz to outside this rule says that when 13.13.13.13 is trying to go to outside with source … Continue reading

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Layer 2 Frame

A layer 2 frame contain following field: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++ | preamble | SFD | DMAC | SMAC | Type/Length | Data + padding | CRC | | 7 byte | 1 byte | 6 byte | 6 byte | 2 byte … Continue reading

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Subnetting

Purpose of this post is: 1> How To find all subnet and host ip in a given network? 2> How to find out the subnet when you are given with a ip and subnet mask? 3> How to break a … Continue reading

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Number system conversion

Binary number system: This number system have two possibility (0,1) Octal number system: This number system have 8 possibility (0,1,2,3,4,5,6,7) [3 bits can represent 8 possibility 2^3=8] Decimal number system: This number system have 10 possibility (0,1,2,3,4,5,6,7,8,9) Hexa decimal number … Continue reading

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