Setup PPTP to access home network transparently

Question

Setup PPTP to access home network transparently

I have Raspberry Pi box connected to home WiFi-router and running pptpd. The local addresses is 192.168.1.32 (eth0) and 192.168.2.1 (ppp0) and local name raspberry.local.

I have iMac connected to the same router with local IP 192.168.1.27 and local name imac.local

I have Macbook somewhere in the Internet connected to Raspberry’s PPTP with 192.168.2.10 on ppp0

This picture shows more clearly.

pptpd configuration

PPTP on Raspberry was installed from this simple script.

/etc/pptpd.conf

option /etc/ppp/options.pptpd
logwtmp
localip 192.168.2.1
remoteip 192.168.2.10-100

/etc/ppp/options.pptpd

name pptpd
refuse-pap
refuse-chap
refuse-mschap
require-mschap-v2
require-mppe-128
ms-dns 8.8.8.8
ms-dns 8.8.4.4
proxyarp
lock
nobsdcomp 
novj
novjccomp
nologfd

/etc/rc.local

…
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -I INPUT -p tcp --dport 1723 -j ACCEPT
iptables -I INPUT  --protocol 47 -j ACCEPT
iptables -t nat -A POSTROUTING -s 192.168.2.0/24 -d 0.0.0.0/0 -o eth0 -j MASQUERADE
iptables -I FORWARD -s 192.168.2.0/24 -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j TCPMSS --set-mss 1356
…

Curent connectivity

Macbook

• can connect to home PPTP and connect to Internet through the home router
• can connect to iMac and Raspberry via local IPs 192.168.1.27 and 192.168.1.32
• can NOT resolve raspberry.local and imac.local

Raspberry

• can connect to iMac and Macbook via local IPs 192.168.1.27 and 192.168.2.10
• can resolve imac.local
• can NOT resolve macbook.local

iMac

• can connect to Raspberry via local IP 192.168.1.32
• can resolve raspberry.local
• can NOT connect to Macbook via local IP 192.168.2.10 (upd: Solved by adding static route to the router)
• can NOT resolve macbook.local

The goal

The goal is to connect and resolve local names from any to any. But I have no idea how to configure this: iptables, avahi, netatalk or somewhere else?

Answer 1

These are 2 separate goals and you have to solve them separately.

For resolution to work: You need to set up a DNS server somewhere (iMac?) and designate it as a resolver in all your devices/computers. Or go with an easier setup, put the name <-> ip address relations into the /etc/hosts file on all your devices/computers

For connectivity: Your iMac simply "does not know" (i.e. no route) how to connect to what is behind the raspberry. However, it DOES work vice-verse since your raspberry is doing NAT for the macbook.

Do you have access to your WiFi router's routing table? If yes, you need to add a route to the PPP network (192.168.2.0/25) via raspberry's external IP address (192.168.1.32).

The exact command or configuration steps, however, depend on the vendor/model of your WiFi router, so I cannot give you a more detailed answer here.