Skip to main content
NetApp Knowledge Base

NFS hangs due to half-open TCP session

  1. Last updated
  2. Save as PDF
Views:
18,030
Visibility:
Public
Votes:
17
Category:
ontap-9
Specialty:
NAS
Last Updated:

 

Applies to

  • ONTAP
  • NFS clients through a stateful firewall

Issue

  • NFS operations hang the CLI, requiring a reboot to restore access to NFS mount  e.g. df ,ls , umount 
  • Client error messages may include:

<linux-client> kernel: nfs: <server> 10.10.10.1 not responding, still trying

  • Packet Traces indicate a repeating loop
    1. The client sends a TCP SYN reusing the same ephimeral port.
    2. ONTAP responds with a challenge ACK, expecting a TCP RST from the client.
    3. The challenge ACK, or RST, is blocked by the firewall; the client retransmits the SYN.

 

 

​

 

Sign in to view the entire content of this KB article.

New to NetApp?

Learn more about our award-winning Support

NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS and the use of this information or the implementation of any recommendations or techniques herein is a customer's responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.