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I recently looked into replacing my Netgear VPN router with a Linux machine. I have configured it and everything worked perfectly including port forwarding. Except that when I tried to connect to a web hosting company's PPTP server, it failed with error 619. The previous router has no such issue.

I tried to connect another PPTP server (running on Linux) and it connected successfully.

In the Linux router, I forwared 1723 and gre to an internal PPTP server. I thought that they are only needed for incoming PPTP connections not for outgoing..

MadHatter
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cuteCAT
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1 Answers1

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PPTP is one of those modules that you have to make sure a particular netfilter module is loaded for to permit it through a NAT.

Make sure nf_conntrack_pptp, and nf_nat_pptp. are loaded (check with lsmod, load with modprobe).

lsmod/modprobe example output.

# lsmod | grep pptp

# modprobe nf_nat_pptp nf_nat_pptp

# lsmod | grep pptp
nf_nat_pptp            20480  0
nf_conntrack_pptp      20480  1 nf_nat_pptp
nf_nat                 57344  3 nf_nat_pptp,nft_chain_nat,xt_MASQUERADE
nf_conntrack          176128  6 xt_conntrack,nf_nat,nf_conntrack_pptp,nf_nat_pptp,nf_conntrack_netlink,xt_MASQUERADE
Zoredache
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    Timely advice. After loading the modules it worked. Thanks – cuteCAT May 09 '13 at 00:00
  • Can you elaborate a little more? – Max Dec 06 '22 at 09:24
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    @Max not really sure what you need more details about? – Zoredache Dec 06 '22 at 22:08
  • @Zoredache could you please provide an example of to employ load and lsmode to achieve this? – Max Dec 07 '22 at 03:31
  • The `lsmod` command lists loaded modules. You simply run it at the command line and it will show you if the modules are loaded. Anyway, I added an example. I do suggest taking time to read the man page for modprobe and lsmod though. – Zoredache Dec 07 '22 at 21:47