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- LPIC-2 Linux Engineer 201
56.
What is the effect of the following /etc/named.conf lines?
listen-on port 53 { 127.0.0.1; };
listen-on-v6 port 53 { ::1; };
listen-on port 53 { 127.0.0.1; };
listen-on-v6 port 53 { ::1; };
- A.The server can be accessed only from the computer on which it ’ s running.
- B.The server will run using a firewall on port 53.
- C.The server will be available to remote computers via both IPv4 and IPv6.
- D.The server will be available to remote computers via IPv6 only.
- Answer & Explanation
- Report
Answer : [A]
Explanation :
Explanation :
| These two lines tell the server to listen for connections only via the IPv4 and IPv6 localhost addresses, effectively limiting access to the local computer only, as option A describes. These options do not create a firewall on any port, so option B is incorrect. Options C and D are both incorrect because the lines ensure that remote computers will not be able to access the server, whether by IPv4 or IPv6. |
57.
Which of the following is a problem that a caching - only DNS server can help solve?
- A.Your ISP ’ s DNS server is reliable but sluggish.
- B.You need to manage the hostnames of 150 computers.
- C.You need to provide a second DNS server for your domain.
- D.Your entire network connection frequently goes down.
- Answer & Explanation
- Report
Answer : [A]
Explanation :
Explanation :
| A caching - only DNS server can help speed up DNS lookups by storing previous lookup requests for a period and optionally bypassing an ISP ’ s DNS server to perform its own recursive lookups. Both features can help overcome the problem described in option A. Option B describes a problem that can be solved by a DNS server that ’ s authoritative for one or more domains, not a caching - only server. Option C requires a second authoritative server, possibly configured as a slave, not a caching - only server. Although a caching - only server can work around a sluggish or unreliable ISP - provided DNS server, it won ’ t help much if the entire network goes down, since real Internet accesses rely on protocols not cached by a DNS server, so option D is incorrect. |
58.
What is the purpose of the following lines in /etc/named.conf ?
zone “1.168.192.in-addr.arpa” {
type master;
file “named.192.168.1”;
};
zone “1.168.192.in-addr.arpa” {
type master;
file “named.192.168.1”;
};
- A.It tells the DNS server to use the file named.192.168.1 to look up IP addresses for names in the in - addr.arpa domain.
- B.It tells the DNS server to use the file named.192.168.1 to look up hostnames when given IP addresses.
- C.It tells the DNS server to ignore ( “ zone out ” ) requests in the 192.168.1. x IP address block.
- D.It tells the DNS server to retrieve the file named.192.168.1 from the master server for the domain in question
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| Zone file definitions in /etc/named.conf tell the DNS server where to look to find mappings of IP addresses to hostnames, or vice versa. The in - addr.arpa pseudo - domain is reserved for reverse DNS lookups — the server returns hostnames when given IP addresses. The file directive points the server to the file that holds the mappings. Thus, option B is correct. Option A is incorrect because reverse DNS lookups return hostnames, not IP addresses. A zone directive is not an instruction to ignore a domain or address block, contrary to option C. The type master line in the example tells the server that it is the master DNS server for this zone, not to retrieve a file from another master server, so option D is incorrect. |
59.
Which of the following tools provides an interactive mode for performing DNS lookups?
- A.named
- B.nslookup
- C.dig
- D.host
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| The nslookup tool, although deprecated, provides a fl exible interactive mode. The BIND server ’ s executable is called named ; this is a DNS server, not a user DNS client. The dig utility can perform complex DNS lookup tasks, but it lacks an interactive mode. The host utility is generally considered the successor to nslookup , but it lacks an interactive mode. |
60.
Which of the following are legal record types in a DNS zone file? (Choose all that apply.)
- A.MX
- B.DNS
- C.ZF
- D.CNAME
- Answer & Explanation
- Report
Answer : [A, D]
Explanation :
Explanation :
| Mail exchanger (MX) and canonical name (CNAME) records are common in forward zone files. There are no such thing as DNS and ZF records. Other common record types include Address (A), Name Server (NS), Pointer (PTR), and Start of Authority (SOA) records. (PTR records are used in reverse zone files.) |
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