D$2.$ Your network stateful Firewall received the following packets, as displayed in the following table in random order. We assume that IPA and IPB are the IP addresses of two hosts in your LAN, and IPC and IPD are the IP addresses of two external hosts.

$\backslash$table$[[$Packet$,$Direction,Source IP$,$Dest. IP$,$Source Port,Dest. Port,SYN$,$ACK$],[$Pa$1,$in$,$IPC,IPA,$80,z,1,1],[$Pa$2,$Out,IPB,IPD,$25,y,1,1],[$Pa$3,$out,IPA,IPC,$z,80,1,0],[$Pa$4,$in$,$IPC,IPA,$23,x,1,1],[$Pa$5,$Out,IPB,IPD,$25,y,0,1],[$Pa$6,$In$,$IPD,IPB,y$,25,1,0],[$Pa$7,$in$,$IPD,IPB,y$,25,0,1],[$Pa$8,$out,IPB,IPD,$80,n,1,1],[$Pa$9,$out,IPA,IPC,x$,23,0,1],[$Pa$10,$In$,$IPD,IPB,$n,80,1,0],[$Pa$11,$out,IPA,IPC,$x,23,1,0]]$

By analysing these packets, reorder the packets in sequence, create a database for a ftateful firewall, and indicate the number of established sessions and the number of halfestablished sessions.

Ans: $($a$)$ Reordering the packets

Packet $\frac{?}{?}$ Direction Source $IP$ Dest. $IP$ Source Port Dest. Port $SYN$ ACK

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