Linux interview questions :FTP

LINUX INTERVIEW QUESTIONS : FTP

One of my friend asked me why there is no answers for So many interview questions, basically most of the interview questions which are on this site are the interviews which happened to me so. At that time I am not able to Answer some of the questions, so from today on words I will try to post all the interview questions with answers, If you feel these answers are wrong you can feel free to comment with proof so that i can modify my posts.

1)What is the difference between TFTP and FTP servers?
A)Both are file transfer servers but slight difference is TFTP server uses UDP protocol and FTP uses TCP protocol. TFTP is good for slow connection paths.

2)What is the port no for FTP?
A)20 for Data and 21 for Control(normally when an interviewer ask's ftp port number just say 21.

3)What is the port no for TFTP?
A)69.

4) How to restrict users to their home directories?
A)By setting up "chroot_local_user=YES".

5)How to restrict total number of users accessing FTP server?
A1) If Vsftpd is running under xinted service, then you can use xineted to get per-service per IP connection limits or
A2) If you run vsftpd in "standalone" mode with the "setting listen=YES", then
you can investigate the setting (e.g.) : "max_clients=10"

6)I want to copy multiple files with out prompting for any info, how can I do that one?
A)Simply do "ftp -i ftpserver" this command will suppress any info displayed on ftp server.
or you can just type prompt ftp prompt to suppress info messages have a look here.

7) Some times Local users cannot log in. How to resolve this issue?
A) Check "local_enable=YES" in your /etc/vsftpd/vsftpd. conf to allow local users to log in.

8) How do we integrate with LDAP( Lightweight Directory Access Protocol )users and login?
A) Use vsftpd's( Very Secure FTPD) PAM(Pluggable Authentication Modules) integration to do this, and have PAM authenticate against an LDAP repository.

9) Can we host different ftp sites on single machine, I mean virtual hosting concept like Apache?
A1) Yes. If you integrate vsftpd with xinetd, you can use xinetd to bind to several different IP addresses. For each IP address, get xinetd to launch vsftpd with a different config file. This way, you can get different behavior per virtual address.
A2) Alternatively, run as many copies as vsftpd as necessary, in standalone
mode. Use "listen_address=x.x.x.x" to set the virtual IP.

10) How to restrict different users with different permissions in vsftpd
A) By setting up "user_config_dir" entry in "vsftpd.conf".


11)How to change vsftpd default port?
A)By setting "listen_port" option in "vsftpd.conf".

12) Vsftpd is reporting times as GMT times and not local times!. How to resolve this?
A) This behavior can be changed with the setting "use_localtime=YES".


13) How to disable certain FTP commands?
A) There are some individual settings (e.g. dirlist_enable) or you can specify a complete set of allowed commands with "cmds_allowed".

14) How does vsftpd support per-IP limits?
A1) If you are running vsftpd standalone, there is a "max_per_ip" setting.
A2) Yes. If you are running vsftpd via xinetd, there is an xinetd config variable "per_source".

15) How Does vsftpd can do bandwidth limiting?
A) settings such as "anon_max_rate" and "local_max_rate" can be used to set this limits.

16) How to restrict some IP's not use my FTP server?
A1) vsftpd can integrate with tcp_wrappers (if built with this support). It is enabled with the setting "tcp_wrappers=YES".

17) Does vsftpd support IPv6?
A) Yes, as of "version 1.2.0".

18) Help! I'm getting messages along the lines of "500 OOPS: vsf_sysutil_bind" when trying to do downloads (particularly lots of small files).
A) "vsftpd-1.2.1" should sort this out.

19) Can we use vsftpd to hiding or denying certain files?
A) Yes. Look at the hide_file and deny_file options.

20)How you can check if there is any syntax error in vsftpd.conf file?
A)Just type vsftpd with out quoats.

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Linux Interview Questions: Experienced

1)How to implement Squid proxy?
2)How to see bandwidth used by ftp user?
3)ow to implement Squid as reverse proxy?
4)How to see logs of Squid proxy?
5)How to see cache in Squid proxy?
6)How to clear Cache in Squid proxy?
7)Totally how many configuration modules are there in Squid proxy?
A)nearly some 127 modules in squid proxy
8)What is the authentication used in Samba when it is used as PDC?
9)Where is the logs present for samba PDC server?
10)Some of the logs in my system are not time stamped how to resolve this ?
11)How to see what is the encryption used by ssl?
11)How to host different domains on with different ip add on single system?
12)How to assigned different ip add to single interface?
13)How to assign different ip addresses to single interface? what is the default gateway to each ip address?

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Linux Interview questions:Experienced

1)What is the difference between Xen and VMware?
A)XEN : Xen is an open-source virtualization solution. The Xen hypervisor acts as a thin layer between the hardware and the operating system, allowing multiple virtual servers to run simultaneously on a single physical server. Each virtual server acts independently of the others, with its own allocated area of RAM and virtual disks.
VMware : VMware is a company that provides virtualization software for x86-compatible computers.

2)Can we install HPUX( (Hewlett Packard UniX) on Vmware?

A)No. Because HPUX can be installed only on PA-RISC or Itanium and Vmware can not emulate this hardware.

3)How to use SAMBA as PDC(Primary Domain Controller)?

4)What is IPchains?

A)Ipchains is a utility for Linux that System Administrators can use to create and modify the ruleset that is used for their host based firewall. These rules are used by a system to decide whether or not it is going to allow a specific remote connection.

5)What is the difference between IPchains and IPtables?

IPchains : Ipchains is a utility for Linux that System Administrators can use to create and modify the ruleset that is used for their host based firewall. These rules are used by a system to decide whether or not it is going to allow a specific remote connection.

IP tables : Iptables is a generic table structure that defines rules and commands as part of the netfilter framework that facilitates Network Address Translation (NAT), packet filtering, and packet mangling in the Linux 2.4 and later operating systems.

6)Explain me how we can use parted command to create partitions ?

7)What is hard NFS(Network File System)? mount and soft NFS mount?

8)Explain briefly about Linux Booting process?

9)What is the difference between TCPdump and Nmap?

10)How to create EXT3 and EXT2 file system?

11)What is the difference between ext2,ext3 and ext4?

12)How to extend LV(Louis Vuitton)?

13)How to see how many VG's are there?

14)Explain the process of configure Apache.

15)How many types of chains are there in IPtables and what are they explain each?

16)What is super block?

17)What is INODE limit? If the file system reaches that limits how to resolve that?

A)Inode is a unique number given to a file in Unix OS. Every file in Unix has a inode number. unix treats directories/folders as a file so they are also having a inode value.

18)What are ACL's in Linux how to implement it in Linux?

19)How to take backup to Tape-drives?

20)How to rectify if tape drive file(hardware file) is missing?

21)What is the difference between RAID01 and RAID10?

22)When using RAID in which cases will you use RAID1 and which cases you will use RAID5?

23)How to implement password less SSH logins?

24)How a user can change a password?

25)How can you get info that my last command executed properly?

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