There is nothing wrong.
(you can reference Internetworking with TCP/IP Vol II by Douglas E.
Comer if you want all the gory details)
20 Octets IP header + 8 octets ICMP header (fixed header of ic_type,
ic_code, and ic_cksum and the next 32 bits depends on ICMP message type)
) + 1472 octets of payload = 1500. Also remember if you are running PPP
on the WAN port it adds it own header and the reduces the size of the
packet that can be sent also as the header size increases.
By going above the MTU size you fragment the ICMP packets and they get
discarded which is a normal thing to do and many routers do it (see icmp
code 4 - Dest unr, frag needed & don't frag). You get a time out as a
response as you should not send ICMP in response to ICMP.
If you search the archive about ICMP fragmentation you can see more info
on what is going on.
Please note that this does not affect TCP, UDP and other protocols
(Though they each do have limits like 4K on UDP).
-- Thomas C Kinnen - <tkinnen@livingston.com> <tkinnen@sobhrach.com> [RADIUS Test Engineer] - LUCENT Technologies RABU "All of the opinions stated above are my own and not my employer's, unless they were given to me by my employer" - To unsubscribe, email 'majordomo@livingston.com' with 'unsubscribe portmaster-users' in the body of the message. Searchable list archive: <URL:http://www.livingston.com/Tech/archive/>