Network Address translation is the process of modifying internet protocol address information. Simply it allows multiple computers to access internet using a single internet protocol address. It also helps us for security by reusing internet protocol address. Network Address Translation is one of the important topic of data communications and networking, in every interview or written exams, most of the questions are asked from network address translation, ip address, ipv4 and ipv6. In this section, we have listed most of the important questions asked during an interview and different written exams. After reading this section, please give your valuable feedback through the comment sections. That will help us to improve the quality of the section and simultaneously you will help others. Any type of suggestions will be highly appreciated.
Here are some important questions and answers on network address translation. It will useful for students for their examination and interviews.
1. What is NAT?
Ans : Network Address Translation (NAT) is intended for informatics address conservation. It allows personal informatics networks that use unregistered informatics addresses to attach to the net. NAT operates on a router, sometimes connecting 2 networks along, and interprets the personal (not globally unique) addresses within the internal network into legal addresses, before packets square measure forwarded to a different network.
As a part of this capability, NAT are often designed to advertise just one address for the complete network to the surface world. This provides further security by effectively concealment the complete internal network behind that address. NAT offers the twin functions of security and address conservation and is usually enforced in remote-access environments.
2. However will NAT work?
Ans : Basically, NAT permits one device, like a router, to act as AN agent between the net (or public network) and an area network (or personal network), which suggests that solely one distinctive informatics address is needed to represent a whole cluster of computers to something outside their network. confer with however NAT Works for a lot of data.
3. However do I piece NAT?
Ans : So as to piece ancient NAT, you would like to create a minimum of one interface on a router (NAT outside) and another interface on the router (NAT inside) and a group of rules for translating the informatics addresses within the packet headers (and payloads if desired) ought to be designed. so as to piece Nat Virtual Interface (NVI), you would like a minimum of one interface designed with NAT modify at the side of constant set of rules as mentioned higher than.
4.What square measure dynamic NAT translations?
Ans : In dynamic NAT translations, the users will establish dynamic mapping between native and international addresses. Dynamic mapping is accomplished by process the native addresses to be translated and therefore the pool of addresses or interface informatics address from that to assign international addresses and associating the 2.
5.What is ALG?
Ans : ALG is AN Application Layer entree (ALG). NAT performs translation service on any Transmission management Protocol/User Datagram Protocol (TCP/UDP) traffic that doesn’t carry supply and/or destination informatics addresses within the application information stream.
These protocols embrace FTP, HTTP, SKINNY, H232, DNS, RAS, SIP ,TFTP, telnet, archie, finger, NTP, NFS, rlogin, rsh, rcp. Specific protocols that imbed informatics address data among the payload need support of AN Application Level entree (ALG).
6.What is transmission control protocol timeout, and the way will it relate to the NAT transmission control protocol timer?
Ans : If the three-party acknowledgement isn’t completed and NAT sees a transmission control protocol packet, then NAT can begin a 60-second timer. once the three-party acknowledgement is completed, NAT uses a 24-hour timer for a NAT entry by default. If AN finish host sends a RESET, NAT changes the default timer from twenty four hours to sixty seconds. within the case of FIN, NAT changes the default timer from twenty four hours to sixty seconds once it receives FIN and FIN-ACK.
7.What is Service supplier PAT Port Allocation improvement for RTP and RTCP?
Ans : The Service supplier PAT Port Allocation improvement for RTP and RTCP feature ensures that for SIP, H.323, and thin voice calls. The port numbers used for RTP streams square measure even port numbers, and therefore the RTCP streams square measure consecutive ulterior odd port range. The port range is translated to variety among the vary such that orthodox to RFC-1889. A decision with a port range among the vary can end in a PAT translation to a different port range among this vary. Likewise, a PAT translation for a port range outside this vary won’t end in a translation to variety among the given vary.
8.What is Session Initiation Protocol (SIP) and may SIP packets be NATted?
Ans : Session Initiation Protocol (SIP) is AN ASCII-based, application-layer management protocol that may be wont to establish, maintain, and terminate calls between 2 or a lot of endpoints. SIP is an alternate protocol developed by the net Engineering Task Force (IETF) for transmission conferencing over informatics. The Cisco SIP implementation allows supported Cisco platforms to signal the setup of voice and transmission calls over informatics networks. confer with summary of SIP for a lot of data.
9.Does NAT support voice co-located solution?
Ans : No. The co-located answer is presently not supported. the subsequent readying with NAT (on constant box) is taken into account a co-located solution: CME/DSP-Farm/SCCP/H323.
10. What’s NAT NVI?
Ans : NVI stands for NAT Virtual Interface. It permits NAT to translate between 2 completely different VRFs. This answer ought to be utilized in part of Network Address Translation on a Stick. confer with NAT Virtual Interface for a lot of data.
IPv4 Addresses And IPv6 Addresses