Using Open VPN service on XG-7100, prevent LAN clients connecting
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If you have an OpenVPN server listening on the WAN it is not designed to be connected to from the inside. It is designed to be connected to from the outside.
Actually, that's normal. You can reach any address on the box from any interface, unless you have rules to block it. Don't forget, pfSense is a router, so if it, for example receives a packet with the WAN interface as destination, on the LAN interface, it will forward it appropriately through 0.0.0.0.
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I know it's completely normal. It's @shapelytraffic that is having trouble grasping that concept.
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@Derelict I saw your rules, what are you representing with "guest" network?
If I block LAN access to the WAN then I assume this will have global impact.
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@shapelytraffic said in Using Open VPN service on XG-7100, prevent LAN clients connecting:
@Derelict To be clear, I'm trying to disable connecting from the inside. We discovered this quite by accident.
That behaviour is normal. If you don't want it, create a rule on the LAN interface to block it.
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No. It won't have global impact. Global addresses are not covered in any of those block rules. Traffic that is not specifically blocked will be passed to the internet by the bottom rules passing traffic to destination any. Guest Network in that example is the IP network of the GUEST interface.
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@JKnott my issue is that any other router on the market which provides a VPN endpoint and client install will only accept client traffic from the public side of the WAN. You cannot go in through the outdoor, as it were. So, if this is "a feature" then I ask, why is it that the feature goes against networking standards? But also, do I really need to implement a ton of firewall rules to make the endpoint behave?
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@shapelytraffic said in Using Open VPN service on XG-7100, prevent LAN clients connecting:
Why does the PFSense implementation of Open VPN go against sane networking theory?
It's not against sane networking theory. PfSense is a router. When it receives a packet, it forwards it as appropriate and that includes to it's own interface addresses. There is no difference between that and any other address out on the WAN. You need to block it with a rule on the LAN interface.
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You are making a common mistake in thinking that WAN address and WAN Network is the "internet". It isn't. Destination any is the internet. WAN address is the address currently assigned on the WAN interface. WAN Network is the subnet of the WAN interface address.
It does not go against networking standards. The rule set is doing exactly what it is being instructed to do, pass the traffic to the OpenVPN server running on WAN address. If that is not what you want, block it.
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@shapelytraffic said in Using Open VPN service on XG-7100, prevent LAN clients connecting:
If I block LAN access to the WAN then I assume this will have global impact.
Block access only to the WAN interface address, not everything out on the WAN and beyond. That is you block that specific address and no other.
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@Derelict what are you representing with "guest" network?
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If you were trying to reach the LAN interface address from the WAN, you'd have to create a rule that would allow that. Going the otherway, pfSense allows all traffic from the LAN, out to the Internet, including the WAN interface address. In some other routers, such as Cisco, you'd have to create a rule just to reach the Internet.
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Here's some info that may help:
The interface settings screen will differ based on the type of interface being dealt with. In pfSense
software, the real distinction between “WAN”, “LAN” and “OPT” interfaces is blurred as they are all capable of handling any role. For historical and ease-of-use purposes, the first two interfaces are WAN and LAN. Additional interfaces start at OPT1 and are numbered from there (OPT2, OPT3, … OPTn)
As soon as you have installed pfSense, you have WAN and LAN interfaces, which are understood to have different roles. The LAN role is to pass everything to the WAN, unless specifically blocked. The WAN role is to block everything, unless specifically enabled.
Try creating a couple of OPT interfaces to get a better idea of how rules are applied.
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@shapelytraffic said in Using Open VPN service on XG-7100, prevent LAN clients connecting:
@Derelict what are you representing with "guest" network?
The subnet of the GUEST interface. I have no idea what it was when I took that screen shot but if the GUEST interface is numbered like this:
192.168.123.1 /24
GUEST Address: 192.168.123.1/32
GUEST Network: 192.168.123.0/24 -
@JKnott This is a production unit so I don't have the luxury of experimenting.
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So spin up a VM to experiment on. It doesn't cost anything.
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@Derelict so, if I understand you correctly, you're saying to block private addresses on the WAN rule set to the WAN IP?
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No. Look at the rule set I posted. The rules go on the interface the connection comes INTO the firewall on. GUEST in that example.
https://docs.netgate.com/pfsense/en/latest/book/firewall/index.html
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@Derelict so, for each internal interface, I need to implement these rules?
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If that is the desired effect to implement your policy, yes.
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@shapelytraffic said in Using Open VPN service on XG-7100, prevent LAN clients connecting:
@Derelict so, if I understand you correctly, you're saying to block private addresses on the WAN rule set to the WAN IP?
One very important thing to remember is that the rules are applied to the interface, not the address. So, you have to put the rule on the interface that the packets will pass through. If you try to reach the WAN address from the LAN, the packets will pass through the LAN interface, but not the WAN interface, so the rules go on the LAN interface.
