nowledge on Network Security SSL/TLS, VPNs (IPsec, GRE), Firewall, IDS/IPSMust have understanding on TCP/IP Header and TCP Flags.Good Knowledge on ISO / OSI Reference Model, TCP/IP Protocol Suite, IP Addressing & Subnetting, ARP.Switching Understanding on VLAN, STPKnowledge of protocols such as SMTP, FTP, DNS, DHCPNetwork troubleshooting experience - familiarity with tools such as Ping, Traceroute.Knowledge on Web proxy, transparent proxy, reverse proxy, Explicit proxy & PAC filesBasic understanding on SSL/TLS, VPNs (IPsec, GRE), Firewall, IDS/IPSKnowledge of HTTP, HTTPSNetwork protocol analyzers Knowledge on anyone of these: tcpdump, Wireshark, fiddler.