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SSH protocol version 2: Each host has a host-specific DSA key used to identify the host. However, when the daemon starts, it does not generate a server key. Forward security is provided through a Diffie-Hellman key agreement. This key agreement results in a shared session key.
When a user successfully logs in, sshd does the following:
If the login is from a tty, prints last login time and /etc/motd (unless prevented in the configuration file or by $HOME/.hushlogin.
If the login is on a tty, records login time.
Checks /etc/nologin and prints contents and quits (unless root).
Changes to run with normal user privileges.
Sets up basic environment.
Reads $HOME/.ssh/environment.
Changes to user’s home directory.
Use in order $HOME/.ssh/rc, /etc/sshrc exists, otherwise runs xauth.
Runs user’s shell or command.
This sets up a secure and user-friendly environment to perform remote system access using an SSH client. Open SSH is currently the best method of remote access.
Documentation
3.14 Document the installation of the operating system, including configuration
The configuration of networking services on a Linux system should include the documentation of all settings. This is important for record keeping, rebuilding services, and to provide records of what has been done. The system settings selected should be clearly documented and include every configuration for any of the services used in networking the system.
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Summary
This chapter explains many of the basics of configuring a Linux system. This task is comprised of three major areas:
The use of linuxconf and netconfig
•linuxconf
•netconfig
•TCP/IP
•Hostname
•DHCP
•DNS
•Gateways
•PPP, SLIP
•NFS
•NIS
•Apache
•SMB/CIFS
Configuration of Internet Services
•Web access
•FTP
•TFTP
•SNMP
Configuration of Remote Access
•rlogin
•TELNET
•OpenSSH Protocol Suite
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STUDY GUIDE
The Study Guide section provides you with the opportunity to test your knowledge about the Linux+ exam objectives that are covered in this chapter. The Assessment Questions provide practice for the real exam, and the Scenarios provide practice with real situations. If you get any questions wrong, use the answers to determine the part of the chapter that you should review before continuing.
Assessment Questions
1.TCP is a _______ oriented protocol? (Fill in the Blank)
A.Connection
B.Connection-less
C.Transmission
D.Transfer
2.PPP is most often used to create?
A.Ethernet point-to-point connections
B.Serial point-to-point connections
C.Parallel point-to-point connections
D.LAN connections
3.NIS and NFS use what TCP/IP system to provide their service?
A.DNS
B.DHCP
C.RPC
D.Yellow Pages
4.Which program can be used to configure not only basic network services but also several network server services?
A.config
B.linuxconfig
C.netconf
D.linuxconf
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5.A host name is most often used to provide which name?
A.IPX
B.FQDN
C.POP3
D.DHCP
6.IP addresses are?
A.24-bit numbers
B.48-bit numbers
C.32-bit numbers
D.8-bit numbers
7.IP addresses are originally assigned by?
A.ISP
B.DHCP
C.DNS
D.IANA
8.DHCP is used to provide what automatically for clients?
A.IP addressing
B.Domain name
C.Internet name
D.IPX addressing
9.When attempting to connect to www.linux.org the return host unknown is returned. Which service is most likely not functioning properly?
A.DHCP
B.NIS
C.DNS
D.WINS
10.What other networking information is usually provided in conjunction with an IP address?
A.Subnet mask
B.DNS
C.Samba
D.PPP
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11.PPP is preferred to SLIP for which reasons (choose all that apply)?
A.Secure password authentication
B.Static IP addressing
C.Dynamic IP addressing
D.Asynchronous communications
12.NFS normally uses which naming service to provide file sharing?
A.DNS
B.NIS
C DHCP
D.WINS
13.What is the most common Linux Web server in use today?
A.IIS
B.Tux
C.FastTrack
D.Apache
14.Samba is used to provide support for which protocol?
A.Network File System
B.Internetwork Packet Exchange
C.Dynamic Host Configuration Protocol
D.Server Message Block
15.What is the most common location of the SMB/CIFS client software installation?
A./usr/samba/bin/
B./etc/samba/bin/
C./lib/samba/bin/
D./bin/samba/
16.What command provides the entire NIS password database?
A.usr/sbin/ypbind
B.ypcat passwd.byname
C.cat passwd ypbind
D.cat ypbind