Chapter 10 Flashcards
Administering Network Security (39 cards)
what is a super server or a super daemon
- > a program that listens for network connections on behalf of other programs
- > when connection is initiated connection is handed to the intended server
name Linux’s 2 primary super daemons
- > inetd
- > xinetd
which of the two primary super daemons are legacy
inetd
what file control launched services of inetd
/etc/inetd.conf
or
/etc/inetd.d/.
what does a typical inetd line look like?
ftp stream tcp nowait root /usr/sbin/tcpd /usr/sbin/in.ftpd -l
how did the inetd program work
it called tcpd which did two things
- > check if client is authorised to use system
- > if authorized ut called the program
where do we still see tcp wrappers
- > ftp server, vsftp
- > if tcp wrappers are used, then the libwrap library is used
how do you determine a network uses tcp wrappers
idd Network Service Daemon | grep libwrap
where is tcp wrappers configured
- > /etc/hosts.allow
- >/etc/hosts.deny
if a host is listed in both /etc/hosts.allow -.deny what happens
allow takes precedence
what is the format of /etc/hosts.allow -.deny
daemon-list : client-list
daemon list are listed in /etc/services
leading trailing dot specifies networks
how do you place an exception in /etc/hosts.allow -.deny
[…] : 192.168.7. EXCEPT 192.168..7.105
what is xinetd
- > extended super daemon
- > provides inetd legacy features
- >
- security options
which file controls the xinetd super daemon
/etc/xinetd.conf
what does the bind option do via xinetd
tels xnetd to listen only on one network interface
name xinetd options
- > bind
- > only_from
- > no_access
- > access_time
where must you set the xinetd features
/etc/xinetd.d/ and place between { … }
if you want to restrict all xinetd servers place it in /etc/xinetd.conf
name security audit tools
- > netstat
- > lsof
- > remote network scanners
- > nmap
- > fuser
what doe the netstat -ap command do
active network sockets that can reveal running servers
what does the lsof program do
lists nomily open files
- used to identify what programs are open in a dir
- > def of file is broad for lsof
- > can be used to check ports
what does the ls -i option do
limit output
how do you use lsof to check ftp servers
# lsof -i :fpt -> ftp can be replaced with 21, ftp port number
what type of utility is nmap
remote network scanner
- > easy to use
- > security audits on your system
what can nmap do
check for open ports
