HI every body!
I just want to ask one question. " don't fragment " bit is set or not set by default in ip header?
thanks a lot and have a nice weekend!
The TTL is set to a value by the source that represents the maximum number of hops it wants for the datagram. Each router decrements the value; if it ever reaches zero the datagram is said to have expired and is discarded.
No default. The TTL is set by the application.
In my experience there is not a generic default for the TTL. It is application or vendor dependent. I have seen a lot of implementations that start at 255, and quite a few that start at 64, and some start at 128.
Here is what I saw
IP header from the host had DF set
IP header in a RIP response from the router
RFC 791 makes no mention of the default setting for the DF bit in the flags field of the IP header.
It depends on the application.
Usually its not set. However, some applications would default to setting it.