NTPD and the Terrible, Horrible, No Good, Very Bad Listening Sockets
Trying to get ntpd to stop creating listening sockets is a royal pain in the ass. Sure, I can set a firewall rule that blocks access to the port on undesired interfaces, but it's more work to make that happen, and it's just not as clean. Here's what I finally ended up doing to stop creating default (0.0.0.0:123 for IPv4 and :::123 for IPv6) listeners and just set a listening socket on one address on my internal interface. Hopefully it helps someone else out. # Add to ntp.conf, in order interface ignore all interface ignore ipv4 interface ignore ipv6 interface listen 192.168.0.1
While there’s not a gaping security window with NTP, I just feel a little safer not having anything listening at all.
Saturday, November 10th 2012 at 8:56 am |
thank you!!! “interface ignore all” doesn’t stop listening on all sockets and this doesn’t make sense… We need to ignore also ipv4 and ipv6, as you said… this is a royal pain in the ass…
Saturday, November 10th 2012 at 10:46 am |
My sentiments exactly! Glad I could help.