LAN DHCP
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Hi, l need help with my Pfsense, everytime there is no internet connectivity, the LAN stops working aswell. I want the LAN to be working even if there is no internet connectivity
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@KBJ there would be no reason for lan to stop working on a wan outage. Dhcp wouldn't stop working, and even if it did - clients should be fine until their lease runs out.
When your wan is out what exactly stops working.. Going to need some details to help figure out what is going on.
But devices on the same lan, you could turn pfsense off and those would still work - unless they are all plugged into pfsense.. What are you running on pfsense for hardware, does it have a switch are you bridging interfaces?
What stops working exactly can you not ping pfsense lan IP, or other IPs on the lan? Dns not resolving for local resources. You mention dhcp, are you unable to get a lease after your lease expires.. Normally the lease time is 2 hours, so devices should maintain in a worse case scenario their IPs for 1/2 that or 1 hour.
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Thanks for the feed back, when the WAN stops working, devices on the network are not able to aquire internal ip addresses and i can,t access the server which hosts student details, Am working at an Institution of learning.
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@KBJ Your wan interface being down should/would have zero to do with your lan dhcp server providing IPs
Are you trying to access this server that resides on a different network than your lan? Are you trying to access it via name that is not resolving, or IP?
When your wan goes down, can you access the web gui via pfsense lan IP and validate your dhcp server is still running? If your client doesn't get an Ip then no it wouldn't be able to access anything.
But again, when a client gets a lease - that lease is good for the length of the lease, ie 2 hours by default.. So even if your dhcp stop working when wan interface of pfsense goes down - which it shouldn't, worse case your devices would still have an IP for 1/2 of the lease time.. This is when a dhcp client renews its lease.
When a device on the lan, lets say its 192.168.1.x wants to access 192.168.1.y - pfsense has zero to do with that conversation - zero!
More than happy to help you - but without some actual info to work with.. Not sure what to tell you..
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The server is on the same LAN
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@KBJ and then pfsense could be off and has nothing to do with 192.168.1.x talking to 192.168.1.y
Your going to have to give us more to go on.. My wan goes out now and then - more than likely most people prob have that issue.. No isp is 100% up..
The only thing that stops working is the internet... Which is how it should work - if yours is doing something different going to need more to go on..
Maybe you have your lease time set for 2 minutes or something, and for some strange reason your dhcp server goes off, or maybe you relay that up through your wan interface..
Pfsense wan interface being down, or the internet not working should have zero to do with dhcp running on pfsense, should have nothing to do with unbound running on pfsense resolving local resources like server.home.arpa, and for sure has nothing to do with 192.168.1.x/24 talking to another IP on the same network 192.168.1.y/24 unless pfsense was a bridge and or there were switch ports and for some reason pfsense is completely off.
So without some actual details of what exactly is happening and how your setup - nobody can help you..
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Yes, clients unable to pull a new lease is one thing but existing clients suddenly unable to use the lease they have is something else.
If pfSense stops responding entirely then DHCP may stop working and DNS may stop which would be an issue if you are trying to access the server by hostname rather than IP.
What is logged in pfSense when this happens?
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The lease time is 7200 seconds (default). The other thing is that the internal network is segmented into VLANS and on each vlan interface dhcp is enabled
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@KBJ
People have probably already gotten tired of repeating this, but I’ll say it again: even for your VLAN-segmented network, it is absolutely not normal for the LAN to lose any connectivity If WAN is down. The fact that DHCP stops working completely when the WAN goes down is a total no-go. Please show or fully describe your network and port configuration. -
@w0w
Just help if you can, your response is very bad -
@KBJ If you not going to provide any actual info, I might as well just close this thread.. You have provided zero that can actually allow anyone to help you.
You haven't even said if your trying to resolve via fqdn (fully qualified domain name) or IP.
Can you access the pfsense web gui.. Can you ping pfsense IP on the lan, can you ping its IP on your other vlan. Can you ping other ips on your lan, the other vlan?
And with @w0w some actual description of your network would be a start.. Does your client actually plug into an interface on pfsense, a switch?
Not sure why you are fixated on dhcp? When has zero to do with anything - Clients don't just loose their IP if the dhcp server turns off.
Can you ping pfsense lan IP from the client on the lan? Can you ping pfsense IP on the lan, can you ping its IP on your other vlan. Can you ping other ips on your lan, the other vlan?
Here is one of my clients on my lan..
$ ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : i9-win Primary Dns Suffix . . . . . . . : home.arpa Node Type . . . . . . . . . . . . : Broadcast IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : home.arpa Ethernet adapter Local: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Killer E2600 Gigabit Ethernet Controller Physical Address. . . . . . . . . : B0-4F-13-0B-FD-16 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.9.100(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Sunday, March 22, 2026 11:38:54 AM Lease Expires . . . . . . . . . . : Saturday, April 4, 2026 4:09:22 PM Default Gateway . . . . . . . . . : 192.168.9.253 DHCP Server . . . . . . . . . . . : 192.168.9.253 DNS Servers . . . . . . . . . . . : 192.168.3.10 NetBIOS over Tcpip. . . . . . . . : DisabledIf I turned off dhcp, my client would still have this 192.168.9.100 IP until April 4th.. With the default dhcp lease time of 2 hours (7200 seconds).. Worse case scenario if dhcp was off your client would still keep its IP for 1 hour (50% of the lease time).
Does your lan and other vlans run on the same wire as your wan? What you describe is not normal - without some details of your network or setup, it is going to be impossible for anyone to help you.
If you are not the admin of this network/pfsense I would suggest you get with your local IT department that runs your network.
mechanic: Welcome to Bob's Auto repair, how can I help you
user: My car is broke, can you fix it.
mechanic: What car do you have, what is actually wrong.
user: its blue
mechanic: ok - what is the make and model of the car and what exactly is broke
user: its broke.
mechanic: ok - does it not start, does it not go in reverse, does it make a weird noise? Does it have gas?
user: I got it 2 years ago, now its broke.
mechanic: Do you see any error lights, like check engine, need some details.
user: Its broke, can you help me or not.. -
Yup, more info needed. Otherwise we are guessing.
What's actually stopping when this happens?
What is shown in the logs at the time?
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Hi, I did some troubleshooting and managed sort out the problem. The LAN interface connecting to the Pfsense is a trunk link, so certain vlans were not allowed. So i did some changes to allow all vlans. Thanks for your feedback.
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@KBJ and how does that have anything to do with
"everytime there is no internet connectivity, the LAN stops working aswell. "
If your trunk was messed up and not correct, it would never work.
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I guess that trunk was carrying both and was being disconnected to test?
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@johnpoz
Am telling u the trunk was messed up, but you still arguing why? -
@KBJ glad you got it sorted.. Lets call it a day.. Sorry but if a trunk was not correct to carry vlans it needed to carry - how was it working when your wan was up? Is all that I am asking.
If you would actually describe your network, and what was actually wrong - it could be helpful for the next guy..
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