아래처럼 테스트 하고 결과를 알려주시면 답변드리겠습니다.

ping -f www.hanaro.com -l XXXX

XXXX는 1400에서 1500중 ping이 되는 가장 큰 값입니다.

이렇게 되면 잘못된것이며
C:>ping -f www.hanaro.com -l 1473

Pinging www.hanaro.com [210.220.163.28] with 1473 bytes of data:

Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.

Ping statistics for 210.220.163.28:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms

이렇게 나오는 최대값입니다.
C:>ping -f www.hanaro.com -l 1472

Pinging www.hanaro.com [210.220.163.28] with 1472 bytes of data:

Reply from 210.220.163.28: bytes=1472 time