subnet mask and default gateway

Subnet Mask:-

The mask is used to detrmine that which part of IP belonged to network or which part belong to host. E.g. if u have a IP 172.16.25.32 and its subnet mask is 255.255.0.0. then the 172.16 is network part , and 25.16 is host part. If subneting is enable then we can use some bit of host part in network .Subnet mask mainly use in subneting. for above example subnet mask is 255.255.255.0 the nwk address become 172.16.25. and the host part is 32.

Default gateway:-

For a simple LAN there is no use of default gateway, It is used when network communicate with other network. it is just like a Main gate of home when a person wanna go to outside from home or come inside he can only do the same by main gate. Same Concept used here. In network if the packet have address of same address then switch direct forward the packet to its desired destination. And if packet have another network address it should be come out from Default gate way. Basically it reduces the collision. subnetmask is just used to identify the class of ip address and its is used for subnetting of ip address for eg:-

ipaddress -192.168.1.2
subnetmask- 255.255.255.0
we can find N/W part that is 192.168.1 and Host part that is 2
the class of ip is C

where as default gateway is a ip address given to a router or ASDL modem which is used to communuicate with other N/Ws or internet

Recover deleted (shift+delete) items

- Thanks Priyanka


1) First go to Run and type regedit

2) Go to:
\HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\EXCHANGE\CLIENT\OPTIONS registry key.



3) Right click options and add new DWORD VALUE (data type is REG_DWORD) and then right click and rename to DumpsterAlwaysOn. It is case sensitive.

4) Then right click and modify and make the value 1 to turn the Recover Deleted Items menu choice on for all folders or enter 0 to turn it off.
5) Then go to Outlook , choose "Recover deleted items" option from the Tools Menu to get back your "permanently deleted" mails!
Note : This procedure can recover mails which were deleted by pressing shift+del in the past 4 days only.