System Admin Q & A

Ques 1: – What is the difference between pop3 and imap protocols?

POP3 (Post Office Protocol) is the most commonly used internet mail protocol. It works on 110 port. It is easy to configure and use. With a POP account you download the mail to your local computer and keep it there. Most of the time it gets deleted off of the mail server after being downloaded. One disadvantage of POP is that once you download it to your computer you won’t be able to check your mail from a different computer since it will already be downloaded onto your own computer. It tends to be slower than IMAP as well.

IMAP (Internet Message Access Protocol) uses a method where all the mailboxes and messages are
maintained on the server. Therefore you can access your e-mail from any location with an internet connection. IMAP is faster than POP because the mail client reads all of the message headers without having to download the entire message. IMAP is also supported in a variety of clients just like POP. One thing to keep in mind is the amount of disk space allocated to your mail on the server may not be enough to hold all of your maiI.IMAP supports the folder synchronization option e.g. if you create any folder on the
client m/c in outlook(mail client) then that folder will automatically created on the mailserver for the account

Ques 2: – What are the Types of Solaris File systems?

  • Disk-based file systems
  • Distributed file systems
  • Pseudo file systems

Ques 3: – What are the requirements for installing AD (Active Directory) on new server?

  • The Domain structure
  • The Domain Name
  • Storage location of the database and log file
  • Location of the shared system volume folder
  • DNS config Method
  • DNS configuration

Ques 4: – What is Caching Name server?

Caching Name server forwards queries and caches the results. This type of name server is not authoritative for any zone. The caching only name server is set up as a host’s primary name server. When a hostname or ip address needs to be resolved, the caching name server forwards a request to another name server or to root name servers in order to determine the authoritative name server for the resolution. Once the resolution has taken place the caching only name server stores the resolved information in a cache for the designated time-to-live period.

Ques 5: – Difference between SSH and Tan“ 0: How to Disable a User Account in Linux

The Primary difference between SSH and Telnet is of security i.e in ssh data transfer between the systems is in encrypted form so it is difficult for the hackers to understand what is going on network.

In Telnet data transfer between the system is in plain text.

SSH used a public key for authentication while Telnet does not use any authentication.
Due to the security measures that were necessary for SSH to be used in public networks, each packet contains less data to make room for the data of the security mechanisms. In order to transmit the same amount of data, you would need to take-up a lot morebandwidth. This is called overhead.

SSH adds a bit more overhead to the bandwidth compared to Telnet.

Ques 6: – How to Disable a User Account in Linux?

# password username -1

Thls might be useful in the situation where you Don’t want to permanently remove the user, but you just want it disabled and no longer able to use the system. The user will still receive emails for example’ but he W1“ 1“” be able to log‘” and Cheek them out.

To re-enable the account, just use below command

#password username -u

Ques 7: – How to detect CPU architecture/bitmode (32-bit or 64-bit) for Linux?

# cat fproc/cpuinfo | grep flags

you will find one of them with name “tm(transparent mode)” or “rm (real mode)” or “lm (long mode)”

1. rm tells, it is a 16 bit processor
2. tm tells, it is a 32 bit processor
3. lm tells, it is a 64 bit processor

Ques 8: – How to make processor online and offline in Solaris?

#psradm -a (processor number) online

#psradm -f (processor number) offline

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