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Yang
Asked: 2013-08-14 16:41:49 +0800 CST

if-up.d script not working?

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I'm trying to make NAT routing persistent on my Ubuntu 12.04 EC2 instance (for OpenVPN; currently I need to run it every time after boot):

ubuntu@vpn:~$ cat /etc/network/if-up.d/vpn-routing
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE

But it's not working:

ubuntu@vpn:~$ sudo iptables -t nat -L POSTROUTING
Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination

Any ideas why? Does it matter that I have ufw enabled? I didn't see anything interesting/relevant in syslog (though I wasn't sure what to look for). Thanks in advance.

boot

2 Answers

  1. I think it's because the file doesn't have a shebang line. It should be something like:

    #!/bin/sh
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE

    Also make sure the file has execution permission:

    sudo chmod +x /etc/network/if-up.d/vpn-routing
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  2. I've had trouble with this myself. One handy way of debugging is to enable the logfile for ppp... sudo touch /var/log/ppp-ipupdown.log

    then when I bring up a ppp session I can see how my script is behaving.

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