fbpx

Server Setup

Fix slow SSH and DNS in CentOS 6

by , , revisited on


We have by far the largest RPM repository with NGINX module packages and VMODs for Varnish. If you want to install NGINX, Varnish, and lots of useful performance/security software with smooth yum upgrades for production use, this is the repository for you.
Active subscription is required.

On a DigitalOcean or Vultr VPS, with IPv6 enabled, you may find that fresh installation of CentOS 6 would have slow SSH connectivity. DNS requests are slow. The solution is easy: you have to allow ICMP traffic for both v4 and v6 in iptables.

iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
ip6tables -I INPUT -p icmpv6 -j ACCEPT

You can run the above command to affect the current firewall state.

After this, save the current rules:

service iptables save

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: