Interview questions

Ques 1: - What could DUP mean when using ping?
Ans: - DUP means duplicate packet.ping will report duplicate and damaged packets. Duplicate packets should never occur, and seem to be caused by inappropriate link-level retransmissions. Duplicates may occur in many situations and are rarely (if ever) a good sign, although the presence of low levels of duplicates may not always be cause for alarm.
Damaged packets are obviously serious cause for alarm and often indicate broken hardware somewhere in the ping packet's path (in the network or in the hosts).
Ques 2: - What is IP Masquerade ?
Ans: - IP Masquerade is a networking function in Linux similar to the one-to-many (1:Many) NAT (Network Address Translation) servers found in many commercial firewalls and network routers. For example, if a Linux host is connected to the Internet via PPP, Ethernet, etc., the IP Masquerade feature allows other "internal" computers connected to this Linux box (via PPP, Ethernet, etc.) to also reach the Internet as well. Linux IP Masquerading allows for this functionality even though these internal machines don't have an officially assigned IP address.
MASQ allows a set of machines to invisibly access the Internet via the MASQ gateway. To other machines on the Internet, the outgoing traffic will appear to be from the IP MASQ Linux server itself. In addition to the added functionality, IP Masquerade provides the foundation to create a HEAVILY secured networking environment. With a well built firewall, breaking the security of a well configured masquerading system and internal LAN should be considerably difficult to accomplish.