Chuah ECS152A/EEC173A TCP connection starts out with congestion window of 1and congestion threshold of 4, how many round trips will it take to download the whole page and display it? (Ignore the time to transmit a TCP segment). 3.(20 points) DNS (a)(4 pt.) What is a whoisdatabase? (b)(4 pt.) Use the ARIN whois database to determine the IP address range used by your university. (c)(4 pt.) Use nslookup to find a Web server that has multiple IP addresses. Does the web server of your university have multiple IP addresses? (d)(4 pt.) Describe how an attacker can use whois databases and nslookup tool to perform reconnaissance on an institution before launching an attack. (e)(4 pt.) Discuss why whois databases should be publicly available. 4.(12points) dig & DNS Cache. (a)(6 pt.) Use the tool dig available on Unix and Linux hosts to explore the hierarchy of DNS servers. Recall that a DNS server higher in the DNS hierarchy delegates a DNS query to a DNS server lower in the hierarchy, by sending back to the DNS client the name of that lower-level DNS server. First read the man page for dig(in particular, the option dig +norecurseStart with a root DNS server (from one of the root servers [a-m].root-servers.net), initiate a 2 ).