Pradeep writes: > I am presently developing a GLDv3 complaint Network driver , > iam facing a strange problem when a do a ftp and ping together iam seeing > following warning message in the ping program. > ICMP Fragmentation needed and DF set from gateway 178.122.70.9 > for tcp from 178.122.70.9 to 178.122.70.56 port 34234
I assume you know that ping (and traceroute) normally print any received ICMP message, and that the message itself is not really the problem. ;-} Internally, the stack creates ICMP messages to itself to communicate conditions just in the same way an external router would. If the transport layer sends something with DF set that exceeds IP's MTU, then the above is what you'll see. > This happens when only when i turn on Large Send Offload in the solaris > driver and > also When ip_path_mtu_discovery is set to 1 . At a guess, it sounds like TCP and IP disagree about the LSO state for this driver, and IP's holding it to the underlying MTU. I'd start debugging by looking at calls to icmp_frag_needed using dtrace, and the ire_max_frag value. (I haven't seen LSO work yet. I'd start by asking the folks who implemented it for help ... [EMAIL PROTECTED] This was PSARC 2006/190. It doesn't appear to be open, but it probably should be.) -- James Carlson, Solaris Networking <[EMAIL PROTECTED]> Sun Microsystems / 35 Network Drive 71.232W Vox +1 781 442 2084 MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677 _______________________________________________ networking-discuss mailing list [email protected]
