[ntp:questions] ntpd as a client when port 123 blocked
nomail at example.com
Sat Apr 26 12:23:47 UTC 2014
On a Linux system we ran into the problem that port 123 has been blocked
for incoming traffic (probably as a general countermeasure against
abuse of badly configured servers, this server was configured correctly).
As it is not possible to change the source port number in ntpd, I
translated the source port using a nat rule:
iptables -t nat -A POSTROUTING -p udp --sport 123 -j SNAT --to-source :12300
Now it again works fine. Of course it cannot be used as a server by
outside clients, but that was not the objective anyway.
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