SELECT DISTINCT(Salary) FROM table ORDER BY Salary DESC LIMIT (n-1),1
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http port is 80
https:443 over ssl using ssl certificate
http 200 ok
http 400 bad request
http 401 unauthorized
403 forbidden
404 not found
500 internal server
502 bad gateway
telnet is network protocol used on lan to provide bidirectional text comm
to check if a port is open
telnet 0 443
$ telnet 192.168.5.5 25
Trying 192.168.5.5...
telnet: Unable to connect to remote host: Connection refused
can be used for email troubleshooting
ssh/scp 22
telnet 23
smtp 25
pop 110
imap 143
ldap 389
mysql 3306
TCP conenction oriented
UDP conection less
Please Physical bits
do data layer packets are encoded into bits
not network switching and routing
throw transport TCP/UDP
sauces session manages session
piza prssentaion encryption ,asci
away applixationfile transfer,email,network software
