Article ID: 649, created on Oct 6, 2008, last review on May 9, 2014

  • Applies to:
  • Virtuozzo containers for Linux


One of the possible reasons of this problem is that many firewalls refuse connections from servers with enabled TCP ECN (Explicit Congestion Notification). To access a site behind such a firewall you will need to disable ECN on the hardware node by running

# sysctl -w net.ipv4.tcp_ecn=0


and adding the following line into /etc/sysctl.conf:

net.ipv4.tcp_ecn = 0

Disabling TCP ECN will not cause any problems.

e8e50b42231236b82df27684e7ec0beb d02f9caf3e11b191a38179103495106f 2897d76d56d2010f4e3a28f864d69223

Email subscription for changes to this article
Save as PDF