System Admin Q & A – VIII

Ques 1: – How to make DHCP server to release IP imidiately if all ips in scope are already assigned ?

i)By reducing lease period

ii) By extending end ip address in the pool

iii) By deleting assigned ip addresses

Ques 2: – Unable to access file share on file server using it’s name (share name) , what can be the solution ?

Ans: – After verifiying DNS funcionality you should check whether host A record for that share has been existed or not. It should be checked on DNS server in forward lookup zone. If does not exist manually create it. or use ipconfig /registerdns command to allow client to dynamically update its host A record (works only if dynamic updates are allowed)

Ques 3: – What is DDNS and why do I need it?

Ans: – Dynamic DNS (described in RFC 2136) allows servers to dynamically update and create records in DNS. Dynamic DNS is used by the Exchange server to create server records and other entries used by the Exchange Servers for things like message routing. In a simple Exchange organization, DDNS is not strictly necessary, but makes administration much easier.

Ques 4: – What is a border server?

Ans: – A border server is an Exchange server that communicates with external servers. In a single server organization, your server is by default a border server. In a multi-server configuration, you may have one or more dedicated servers that communicate directly or indirectly with foreign servers and then pass the mail to other internal Exchange servers.

Ques 5: – How do I restrict a user or domain from sending mail to my users?

Ans: – First, add the address or domain you wish to filter to the Filtering Tab of the Message Delivery Global Settings. Next, you need to apply the filter to the SMTP virtual server you wish to filter. (Administrative Group | Server | Protocols | SMTP | <SMTP Virtual Server> | Properties | Advanced | <select the IP address for which you wish to enable filtering> | Edit | Apply Filter). Normally, you would only want to apply message filtering to the border SMTP servers (servers that communicate directly with External servers).

Ques 6: – What is HTTP Tunneling

Ans: – HTTP Tunneling is a security method that encryptes packets traveling throught the internet. Only the intended reciepent should be able to decrypt the packets. Can be used to Create Virtual Private Networks. (VPN)

Ques 7: – You wish to create a link to the /data directory in bob’s home directory so you issue the command ln /data /home/bob/datalink but the command fails. What option should you use in this command line to be successful.

Ans: – Use the -F option
In order to create a link to a directory you must use the -F option

Ques 8: – What command should you use to check the number of files and disk
space used and each user’s defined quotas?

Ans: – repquota

The repquota command is used to get a report on the status of the
quotas you have set including the amount of allocated space and amount
of used space.

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