I have the following situation.
The home network is on 192.168.1.0/24 and uses a Zyxel USG50 which is able to handle IPSec tunnels. The remote VPS runs Ubuntu 16.04 and hosts a PPTP server (10.0.0.1) which assigns addresses 10.0.0.100-200 to the clients. The PPTP server works perfectly and the clients can surf the internet without problems of any sort.
Now I'm setting up a IPSec tunnel to be able, through a PPTP connected device, to access my home network devices. Anyway, communication seems to work one way only: I can ping VPN connected devices (say, 10.0.0.100) from home network (say, 192.168.1.4) but not viceversa. Also the VPS can't ping devices on the 192.168.1.0 network (the packets go outside on the internet)
ipsec.conf
conn home
authby = secret
keyexchange = ikev1
ikelifetime = 86400
lifetime = 28800
ike = aes256-sha512-modp2048!
esp = aes256-sha512-modp2048!
auto = add
left = %any
leftsubnet = 10.0.0.0/24
leftfirewall = yes
right = (my_ddns_home_address)
rightid = %any
rightsubnet = 192.168.1.0/24
ipsec status
Security Associations (1 up, 0 connecting):
home[1]: ESTABLISHED 30 minutes ago, my_vpsip[my_vps_ip]...my_home_ip[my_home_ip]
home{1}: INSTALLED, TUNNEL, reqid 1, ESP SPIs: ce9b32e6_i 96369de8_o
home{1}: 10.0.0.0/24 === 192.168.1.0/24
ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:89426 errors:0 dropped:0 overruns:0 frame:0
TX packets:89426 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:30719387 (30.7 MB) TX bytes:30719387 (30.7 MB)
ppp0 Link encap:Point-to-Point Protocol
inet addr:10.0.0.1 P-t-P:10.0.0.100 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1396 Metric:1
RX packets:32314 errors:0 dropped:0 overruns:0 frame:0
TX packets:44911 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:3108413 (3.1 MB) TX bytes:49298247 (49.2 MB)
venet0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet addr:127.0.0.2 P-t-P:127.0.0.2 Bcast:0.0.0.0 Mask:255.255.255.255
UP BROADCAST POINTOPOINT RUNNING NOARP MTU:1500 Metric:1
RX packets:12701126 errors:0 dropped:0 overruns:0 frame:0
TX packets:11210758 errors:0 dropped:7605 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:11729004253 (11.7 GB) TX bytes:3015436822 (3.0 GB)
venet0:0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet addr:vps_public_ip P-t-P:212.24.96.165 Bcast:vps_public_ip Mask:255.255.255.255
UP BROADCAST POINTOPOINT RUNNING NOARP MTU:1500 Metric:1
iptables -L -n -v
Chain FORWARD (policy ACCEPT 1060 packets, 436K bytes)
pkts bytes target prot opt in out source destination
3 180 ACCEPT all -- venet0 * 192.168.1.0/24 10.0.0.0/24 policy match dir in pol ipsec reqid 1 proto 50
9 540 ACCEPT all -- * venet0 10.0.0.0/24 192.168.1.0/24 policy match dir out pol ipsec reqid 1 proto 50
ip route show table 220
192.168.1.0/24 via my_home_ip dev venet0 proto static src 10.0.0.1
