Description of problem:
  Prepare a win2003 i386 guest with e1000 driver, can't ping the guest from host, but other machines on the different subnet can ping guest, and guest can ping others as well, switch the host to rhel5.8 release (2.6.18-308.el5xen), this problem occur again.
  rhel5.7 release (2.6.18-274.el5xen) and rhel5.6 release (2.6.18-238.el5xen) will lead to BSOD, it's because of BZ723755.
  Win2003 x64 guest won't have this problem


Version-Release number of selected component (if applicable):
Host: RHEL5.9 2.6.18-339.el5xen x86_64, xen-3.0.3-140.el5
      RHEL5.8 2.6.18-308.el5xen x86_64, xen-3.0.3-135.el5

Guest: Win2003 i386 hvm + e1000 driver


How reproducible:
100%


Steps to Reproduce:

1.Prepare a win2003 i386 guest with e1000 driver installed, and e1000 is the only nic on the guest.

2.ping the guest from host(start tcpdump on both side)

3.ping the host from guest(start tcpdump on both side)


Actual results:
  Host can't ping guest, but other machines from different subnet can ping.
  use tcpdump for both side to capture icmp package:
      host ping guest: guest will got ICMP-ECHO package
      PING 10.66.103.136 (10.66.103.136) 56(84) bytes of data.
      From 10.66.100.101 icmp_seq=1 Destination Host Unreachable
      From 10.66.100.101 icmp_seq=2 Destination Host Unreachable
      From 10.66.100.101 icmp_seq=3 Destination Host Unreachable
      From 10.66.100.101 icmp_seq=4 Destination Host Unreachable
      From 10.66.100.101 icmp_seq=5 Destination Host Unreachable
      From 10.66.100.101 icmp_seq=6 Destination Host Unreachable
      no ICMP packages captured on both side

      guest ping host: host won't got any ICMP package
      Request timed out.
      Request timed out.
      Request timed out.
      Request timed out.
      no ICMP packages captured on both side


Expected results:
  Host could ping guest and guest could ping host as well.
  Maybe this is a bug relate to default Microsoft e1000 driver problem, not our bug, but should added a technical note.


Additional info:
1.The following release can't reproduce this problem becuase of BSOD
      RHEL5.7 2.6.18-274.el5xen x86_64
      RHEL5.6 2.6.18-238.el5xen x86_64
  related bug:
  BZ723755 - win2003 i386 guest BSOD when created with e1000 nic
  https://bugzilla.redhat.com/show_bug.cgi?id=723755

2.No such problem on Win2003 x86_64, and i found the default e1000 driver version is different from i386

3.Attention: After updated the e1000 driver to Intel latest version, this problem disappear.
   Original Win2003 i386 e1000 driver
    provider:Microsoft
    date:10/1/2002
    version:6.3.6.31
    
   Intel Official e1000 driver(http://downloadcenter.intel.com/detail_desc.aspx?agr=Y&DwnldID=18719)
    provider:Intel
    date:8/20/2008
    version:8.10.3.0

   Original Win2003 x86_64 e1000 driver
    provider:Microsoft
    date:10/1/2002
    version:8.1.8.0

4. no such issue with rtl8139, tested with floowing matrix:
  RHEL5.9          2.6.18-339.el5xen
  rhel5.8 release (2.6.18-308.el5xen)
  rhel5.7 release (2.6.18-274.el5xen)
  rhel5.6 release (2.6.18-238.el5xen)