pfSense behind ISP modem (Double NAT) trouble
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pfSense on a device using just one physical NIC ?
Never saw one myself, but I saw the movie.
From what I recall, you do need a L2/L3 capable switch.edit :
Stupid me, forgot the source : pfsense with one NIC. -
Router-on-a-stick is a valid method, though I wouldn't use it unless you really can't have two NICs.
Anyway that should work as long as your switch is configured correctly. And it appears to be at least mostly if LAN clients are able to pull a DHCP lease. Is that lease actually coming from pfSense?
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@clarkx86 Hmmm, your "anti lockout rule" looks overly permissive... I'd say you have opened up to the world actually... remove all of them...
You already have an anti-lockout rule on LAN, where it should be... If you need to access your pfsense UI from the outside, it's generally adviced to use a VPN, so you access it from the inside instead.
Otherwise the LAN rules look fine even though the default rule normally has the LAN subnet as the source, I think, unless I changed it myself...
Outside of those two things, it all looks good which leads me to think it's you switch setup that isn't entirely correct. So you have to make sure that the port attached to pfsense is TAGGED for VLAN 10, and the ports used for the PC's and other devices are UNTAGGED VLAN 10 (and have PVID 10 set as well).
What switch are you using? -
@Gblenn said in pfSense behind ISP modem (Double NAT) trouble:
@clarkx86 Hmmm, your "anti lockout rule" looks overly permissive... I'd say you have opened up to the world actually... remove all of them...
Normally I wouldn't do that, but I wanted to access the pfSense from the modems network before setting all VLANs and PVIDs and I thought because it's actually behind my modem with it's own firewall (I have no ports open at all), it should be as "safe" as all my other hosts on the modems main network. Correct me if I'm wrong however!
@Gblenn said in pfSense behind ISP modem (Double NAT) trouble:
the ports used for the PC's and other devices are UNTAGGED VLAN 10 (and have PVID 10 set as well).
I made sure and it does work, a device attached to the VLAN 10 port even gets a IP from the pfSense LAN DHCP (192.168.10.102).
@Gblenn said in pfSense behind ISP modem (Double NAT) trouble:
What switch are you using?
I use a Zyxel GS1920-8HPv2.
The weird thing is that I can ping other hosts on the VLAN 10 192.168.10.0/24 network, except the pfSense itself 192.168.10.1, though I think the rules should allow that?
Maybe it's a problem with the single NIC and the WAN on VLAN 1, but I'm not sure how, since I do get an IP address on both interfaces.
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Try running a packet capture in pfSense whilst trying to ping it from something in the LAN. See what it actually arriving there.
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@clarkx86 said in pfSense behind ISP modem (Double NAT) trouble:
Normally I wouldn't do that, but I wanted to access the pfSense from the modems network before setting all VLANs and PVIDs and I thought because it's actually behind my modem with it's own firewall (I have no ports open at all),it should be as "safe" as all my other hosts on the modems main network. Correct me if I'm wrong however!
Yes it's ok in this case, since you do have a firewall in front of pfsense.
@clarkx86 said in pfSense behind ISP modem (Double NAT) trouble:
I use a Zyxel GS1920-8HPv2
I took a peek at the manual for that switch but I'm afraid I couldn't really make sense of the VLAN settings in it...
Is there a status screen where you see your switch ports and their VLAN settings somehow?? If so perhaps you can paste it here?
Also the VLANs tab in pfsense (under interfaces), I suppose it has the LAN interface there doesn't it?? -
@Gblenn said in pfSense behind ISP modem (Double NAT) trouble:
Is there a status screen where you see your switch ports and their VLAN settings somehow??
Yes, here is my VLAN overview. Mind you this sitting on my desk as a test setup. Port 1 is the pfSense with tag 1 & 2 and Port 2 on the switch is my test device attached to VLAN 10. Ignore Port 9, it's for trunking to another switch.
The modem is just connected in the default VLAN 1 network.
@elvisimprsntr said in pfSense behind ISP modem (Double NAT) trouble:
Pick up a used Qotom for ~$50 and save your sanity trying to use router-on-a-stick VLANs
This is a good idea, but unfortunately I'm stuck with hardware (it is a Realtek NIC I believe).
Maybe I should set the modem to a different VLAN ID than the default 1 and also use VLAN for the WAN interface...
@stephenw10 said in pfSense behind ISP modem (Double NAT) trouble:
Is that lease actually coming from pfSense?
Yes, I can confirm because the host configures itself with the correct nameservers I also specified in pfSense and has a correct IP in the range I assigned in the DHCP server settings on the LAN interface.
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I would remove port 2 as an untagged port on VLAN1 in the switch. Though that shouldn't actually prevent it working.
Then I'd pcap in pfSense and see what's happening.
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@clarkx86 said in pfSense behind ISP modem (Double NAT) trouble:
Yes, here is my VLAN overview. Mind you this sitting on my desk as a test setup. Port 1 is the pfSense with tag 1 & 2 and Port 2 on the switch is my test device attached to VLAN 10. Ignore Port 9, it's for trunking to another switch.
I kind of looks ok, although it's confusing to see that ID 10 is listed as untagged for ports 1 - 10, which includes port 2. Perhaps it's a limitation of the UI, and I would have expected it to read 1, 3-10. Sicne you don't want any VID 1 traffic ending up on port 2... Are you sure you are actually seeing the devices picking up DHCP from pfsense or is it from the modem?
Port 1 being Tagged for VLAN 10 looks good though.
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@Gblenn said in pfSense behind ISP modem (Double NAT) trouble:
I kind of looks ok, although it's confusing to see that VID is listed as untagged for ports 1 - 10, which includes port 2. Perhaps it's a limitation of the UI, and I would have expected it to read 1, 3-10. Sicne you don't want any VID 1 traffic ending up on port 2... Are you sure you are actually seeing the devices picking up DHCP from pfsense or is it from the modem?
I set port 2 to PVID 10 so the traffic from this port always falls into VLAN 10, I will try to disable this port for ID 1 however.
Also I will do a pcap and report my results later.
