On Tue, Apr 13, 2004 at 09:46:21AM -0500, Kevin D. Kinsey, DaleCo, S.P. wrote:
Vr HL TOS Len ID Flg off TTL Pro cks Src Dst 4 5 00 05dc 07bd 0 0000 3f 01 1677 192.168.0.2 192.168.0.80
The device (router?) is sending a host unreachable message which can be for a variety of reasons, the most common being that there is no route available to the destination. What address are you pinging from though? You are trying to ping with a packet size of 2048 bytes (-s) but the MTU of Ethernet is 1500 bytes.
First off, thank you *very much* for taking time to explain this.
A further question, if I may ... from a FBSD box at 192.168.0.2,
I can ping 192.168.0.2 up to { -s 65507 }. Windows XP at *.*.*.10
responds as long as { -s < 25153 } ... if Ethernet Maximum is 1500,
and that's the reason for the error <?> why doesn't FreeBSD, or
even Windows, elicit a similar response? Nah, maybe that's a bad
question ... they aren't the same OS ... :-(So, MTU is an OS feature/stat rather than general Ethernet?
You don't need to understand the information below to troubleshoot this
but here is an explanation anyway :) It's just a dump of the IP packet headers that came back in the destination host unreachable message:
Vr 4 IP version 4
HL 5 Packet header length
TOS 0 Type of Service: Routine traffic
Len 05dc Packet length in hex (1500 bytes)
ID 07bd Identification - unique number to tell the ICMP packets apart
Flg 0 Flags - 3 bits: 0 (reserved), 0 (fragment if necessary), 0 (last fragment)
Off 0000 Fragment offset (not used since it is not a fragment)
TTL 3f Time to Live in hex (63 hops) - number of hops before packet is discarded
Pro 01 IP protocol type (01 = ICMP, what ping uses)
Cks 1677 Packet header checksum
Src Source address that sent the "host unreachable" message
Dst Recipient of the "host unreachable" message - your machine
Thank you. This was what I was fishing for, an explanation, for me to learn *something* from this experience, besides the fact that this "other" OS seems to behave badly in the presence of any kind of adverse networking conditions, including big pings and any kind of real latency ...
We've just decided we're going to have to baby this one. Wish it was a *BSD instead; seems like nothing much bothers BSD ;-)
Kevin Kinsey DaleCo, S.P. _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
