Chapters 10 & 11
Iterative Queries
A DNS query that does not demand a resolution, which means the server provides the information only if it already has that information available.
A forwarder
A DNS service you would configure on the LAN to use a public DNS server to resolve queries for external domains
What must be installed on a server to use secure (HTTPS) connections?
A digital certificate and the corresponding private key.
What use is a PTR DNS record?
A pointer maps an IP address to a host name enabling a reverse lookup. Reverse lookups are used (for example) in spam filtering to confirm that a host name is associated with a particular IP address.
What type of DNS record resolves a host name to an IPv6 address?
AAAA
VoIP gateway
Component in a VoIP network that allows calls to be placed to and from phone/public phone network
When configuring multiple DHCP servers for redundancy, what should you take care to do?
Configure the servers with nonoverlapping address scopes.
What is the function of a dig subcommand such as +nostats?
Control what is shown by the tool. You can use these commands to suppress certain kinds of output, such as sections of the response from the DNS server.
Recursive queries
DNS servers take responsibility for resolution. Will contact other DNS servers as required.
The process of a DHCP server initializing client
Discover —> Offer —> Request —> Acknowledge
SIP
Enables the location of user agents via a specially formatted URL
True or false? An HTML web page is sent as the response to a client in an HTTP header field.
False. The HTML is the payload of the HTTP packet
Protocol for client to manage mail subfolders on remote mail server
IMAP or IMAP Secure (IMAPS)
What address is used to contact a DHCPv6 server?
IPv6 does not support broadcasts, so clients use the multicast address ff:02::1:2 to discover a DHCP server.
In a stateless environment, what sort of information does DHCPv6 provide?
In a stateless environment, the host autoconfigures an address using a network prefix provided by the router (typically). DHCPv6 is then used to provide the IPv6 addresses used to access network services, such as DNS or SIP gateways.
A Firewall for a Linux web server to communicate with a database server over TCP/3306. What database is being used?
MySQL
When you configure name server addresses as part of a host's IP settings, do you need to specify servers that perform iterative queries only or ones that accept recursive queries?
Recursive queries
What type of DNS record is used to prove the valid origin of email?
Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) records can be used to validate the origin of email and reject spam. These are configured in DNS as text (TXT) records.
The standard TCP/IP port for printing
TCP/9100
TFTP vs FTP
TFTP - only supports GET and PUT commands, works over UDP FTP - can also use directory browsing, file deletion, etc. works over TCP.
What happens if a message sent via SMTP cannot be delivered?
The server generates a non-delivery report (NDR) with an appropriate error code and discards the message.
nslookup command
To start nslookup in interactive mode
DHCP options can be configured on a per-scope basis.
True
What types of DNS records have priority or preference values?
Typically mail (MX) and service (SRV) records.
When a DHCP client initializes all communications are sent using what?
UDP. The server listens on port 67 and the client listens on port 68.
