Team blog of MCS @ Middle East and Africa

This blog is created by Microsoft MEA HQ near shoring team, and it aims to share knowledge with the IT community.With its infrastructure and development sides,It brings to you the proven best practices and real world experiences from Subject Matter Experts
Follow Us On Twitter! Subscribe To Our Blog! Contact Us

Unstable connectivity behaviour on Hyper-V guests

Unstable connectivity behaviour on Hyper-V guests

  • Comments 2
  • Likes

Environment:

Windows Server 2008 R2 with Hyper-V Role

Symptopms:

 VMs on a certain Hyper-V host were having bizzare connectivity patterns, when I tried to ping other machines, I would get three types of ICMP reponses for the same ICMP request. below is a snapshot

 

The network configuration is shown below, with the stable and the unstable communication paths

 

 

Resolution:

1- disable netDMA on the Host NIC (check this article http://support.microsoft.com/kb/951037)

2- Disable Large Send Offload on the Host NIC (in the advanced properties of the NIC)

 

Comments
  • What was the caused the issue?  Was it related to the type of hardware or network adapter?  Did the network issues traverse other protocols beyone ICMP?

  • Hello Phil, this issue was occuring for all networking protocols not just ICMP. With regards to the cause, it is hardware specific. This happens only for poorly written hardware drivers, and it is not a Hyper-V issue.

Your comment has been posted.   Close
Thank you, your comment requires moderation so it may take a while to appear.   Close
Leave a Comment