What is the default TTL (time to live) on a router that an IP packet...

TTL (Time to Live) is a field in the IP header that limits the number of hops a packet can travel. Each router that processes the packet decrements the TTL by 1. When TTL reaches 0, the packet is dropped.

Default TTL values vary by operating system, but in RouterOS and many Linux-based systems, the default TTL is 64.

A. 60 → Incorrect, used in some systems but not the MikroTik default

B. 30 → Incorrect

C. 1 → Incorrect; would allow only one hop

D. 64 →✔Correct

Extract from Official MTCNA Course Material – TTL Field Explanation:

"The default TTL in RouterOS and most Unix-like systems is 64. Each router decrements this by 1 until the packet is discarded."

Extract from René Meneses Study Guide – IP Protocol Details:

“TTL is initialized to 64 by default in MikroTik RouterOS.”

Extract from MikroTik Wiki – IP Protocol Section:

"RouterOS sets default TTL of 64 unless manually configured otherwise."

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