Bambu Lab LAN mode not working: fixes, ports and Developer Mode

When Bambu Lab LAN mode stops working, check the network before the printer: the computer and printer must share one subnet with no guest-network isolation, and the firewall must let Bambu Studio hear the printer’s discovery broadcasts. Then confirm the access code matches the one on the printer’s screen. If the printer still does not show up, bind it by IP address and access code, which skips discovery.

First-time setup is in how to run a Bambu Lab printer in LAN-only mode. Menu names and messages below follow Bambu Lab’s documentation and Bambu Studio’s source as of October 22, 2026.

Why is Bambu Lab LAN mode not working?

Bambu Lab LAN mode usually fails for one of five reasons: the computer and printer sit on different subnets or a guest network that blocks device-to-device traffic, a firewall or VPN blocks Bambu Studio, the access code is wrong or was refreshed, the printer is still in cloud mode, or third-party software lacks Developer Mode.

What you see	Likely cause	What to check
The printer never appears in Bambu Studio’s Device list	Discovery broadcasts do not reach the computer: another subnet or VLAN, client isolation, or a firewall blocking UDP 1990 and 2021	Steps 2 to 5 below
“Failed to connect to printer” or another dialog error	Depends on the message	Message table
Connected, but print jobs never arrive	File transfer blocked, storage full or slow; on an X1, no microSD card	Step 8
The network plug-in will not install	Antivirus, VPN, proxy or another app blocking it	Bambu’s plug-in guide
Blank camera, or “Missing LAN IP of printer”	Discovery failure, or LAN liveview is off	Camera checks
OrcaSlicer or Home Assistant shows status but cannot print or move the printer	Bambu’s authorization control	Developer Mode
Bambu Handy cannot see the printer, or printing from outside the home fails	Expected: LAN mode drops the Handy app and remote printing	Nothing to fix; print from Bambu Studio on the same network

Discovery is the weak point. Bambu Studio finds a LAN-mode printer by listening for broadcasts the printer sends, and Bambu’s P1 troubleshooting page says the router “will only forward these broadcast packets in the same LAN.” The computer needs the printer’s subnet, “such as 192.168.2.X”, with only the last of the four numbers different.

A ping can succeed between two subnets while discovery fails, because the broadcasts stay in their own subnet. Bambu adds that blocked device-to-device traffic “commonly occurs on Guest networks where Device/Client Isolation is enabled.”

A computer on 5 GHz and a printer on 2.4 GHz can still use LAN mode if both networks share one subnet. The band only decides whether the printer joins a network at all. Bambu documents 2.4 GHz only for the A1, the P1 series and the X1E, and 5 GHz support for the H2S, P2S and X2D. The A1 spec sheet lists 2412 to 2462 MHz under FCC and IEEE 802.11 b/g/n.

Running Bambu Farm Manager’s server on the same computer as Bambu Studio can also block discovery: Bambu says “a port conflict may occur.” In that case, bind by IP address.

What does “Failed to connect to printer” mean in LAN mode?

It means Bambu Studio stopped hearing from the printer. Bambu’s wiki says the error appears when Bambu Studio “is unable to receive printer status messages for a certain time (timeout is 30s).” In LAN mode those messages travel over MQTT (the messaging protocol the printer uses for control and status) on TCP 8883. Check that the printer is still on the network, that its home screen shows no MQTT errors and that nothing blocks that port.

Bambu Studio’s IP and access code dialog names the failure more precisely:

Message	What it means	Fix
“Failed to connect to printer.”	No answer from that IP address	Ping it (step 2), check the firewall (step 4)
“Connection failed, please double check IP and Access Code”	The IP and access code check failed	Read both from the printer again; the code may have been refreshed
“The printer mode is incorrect, please switch to LAN Only.”	The printer is in cloud mode	Turn on LAN Only on the printer, then connect again

Which ports does Bambu Lab LAN mode use?

Bambu Lab LAN mode uses TCP 8883 for MQTT control and status, TCP 990 plus 50000 to 50100 for file transfer, TCP 322 or 6000 for the camera, and UDP 1990 and 2021 for discovery, according to Bambu Lab’s port list. LAN mode needs none of the cloud ports or domains.

Sorted by port number:

Port	Protocol	Used for	Direction
123	TCP/UDP	NTP time sync (listed for cloud and LAN mode)	Printer to internet time servers
322	TCP, RTSP over TLS	Camera stream on X1, P2S and H2 series	Computer to printer
990	TCP, FTP over TLS	Sending print files	Computer to printer
1990	UDP, SSDP multicast to 239.255.255.250	Discovery	Printer to computer
2021	UDP, broadcast to 255.255.255.255	Discovery	Printer to computer
6000	TCP over TLS	Camera stream on P1 and A1 series	Computer to printer
8883	TCP, MQTT over TLS	Control and status	Computer to printer
50000 to 50100	TCP	FTP, listed by Bambu with 990	Computer to printer

Bambu’s list gives the camera as “322/6000” with no per-model split. Its P1 troubleshooting page names 6000 for the P1. The community OpenBambuAPI documentation describes RTSPS (encrypted RTSP video) on port 322 for the X1, P2S and H2 series, and the 6000 stream for the A1 and P1. On the H2S and H2D firmware it tested, OpenBambuAPI found port 322 closed until the LAN liveview switch was on.

Cloud mode adds other ports (80, 443, 8080, 3000 and the remote video ranges). For LAN mode, Bambu says “the Domain name/IP list can be ignored.”

Printer on its own VLAN. Allow the computer to reach TCP 8883, 990, 50000 to 50100 and the camera port on the printer’s IP address. Discovery broadcasts will not cross into another VLAN on their own. Relay UDP 1990 and 2021 with your router’s multicast or SSDP relay if it has one, or bind the printer by IP address.

How do you fix a Bambu Lab printer that will not connect in LAN mode?

Put the computer and the Bambu Lab printer on one non-guest network, ping the printer’s IP address, re-enter the access code shown on its LAN Only page, and allow Bambu Studio through the firewall and VPN. If the printer still does not appear, bind it by IP address and access code under Device, No Printer, Bind with Access Code.

How to fix Bambu Lab LAN mode, step by step

1. Read the printer’s own values. On the printer’s LAN Only page, confirm LAN Only is on and note the IP address and access code. Bambu’s P1 release notes say that after the code is refreshed, “Bambu Studio will disconnect and needs the new access code to connect to the printer again.”
2. Ping the printer. On the computer, run ping followed by the printer’s IP address. If replies time out or show packet loss or high latency, Bambu says to “move both to a non-guest SSID or disable Device/Client Isolation for that network.”
3. Compare the subnets. The computer’s IP address should differ from the printer’s only in the last number. On Windows 11 it is listed as IPv4 address under Settings, Network & internet, Wi-Fi, your network. If the two do not match, discovery cannot work: put both on one network or go to step 5.
4. Test without the firewall, VPN and proxy. Bambu says to make sure they are “not blocking Bambu software from accessing the network,” and to disable them temporarily if unsure. If the printer then appears, turn them back on and allow Bambu Studio to receive UDP 1990 and 2021 and reach the TCP ports above. Windows 11 sets a new network to Public by default, which Microsoft says hides the PC from other devices. Make sure the firewall rule covers that profile, or set a trusted home network to Private under Network profile type on the same Settings screen.
5. Bind by IP address. Bambu says a LAN-mode printer can take 20 to 60 seconds to appear in the Device list with a lock icon. If it does not, open Device, then No Printer, then Bind with Access Code. Enter the IP address and access code. On macOS the dialog also asks for the printer’s serial number (SN) and model, found in the device information on the printer screen. Bambu Studio does not store the IP address, so you re-enter it after every restart; a DHCP reservation (a fixed address the router always gives the printer) keeps that address from changing.
6. Test on a phone hotspot. Join the printer and the computer to the same 2.4 GHz phone hotspot. If LAN mode works there, Bambu says the original network (router settings, firewall or network stability) is the cause.
7. Check the router. If your router has “UPnP” and “IPv4 Multicast Streams” settings, enable them, as Bambu’s P1 page advises. Remove any firewall, port filtering or access control rules that block the ports above.
8. Test file transfer directly. If prints never arrive, point an FTP client such as FileZilla at the printer’s IP address on port 990. Log in as user bblp with the access code as the password, and upload a file larger than 1 KB. If that fails, restart the printer. Bambu says slow or full storage also fails transfers: delete old files, or format or replace the card. On an X1, insert a microSD card, because Bambu says starting a LAN-mode print from Bambu Studio needs one.
9. Update Bambu Studio and the firmware. Bambu Studio needs the Bambu Network plug-in to send files over LAN, and installing it needs an internet connection. Recent firmware addressed LAN faults: P1 01.09.01.00 fixed print jobs that “could be sent successfully in LAN mode, but the printer would not respond,” and X1 01.11.00.00 resolved “occasional delays when sending print jobs from Bambu Studio.” An offline printer takes firmware from a card or USB drive (see the LAN-only guide). If the update stalls, see Bambu Lab firmware update stuck.
10. Send logs to Bambu Lab. If every check passes and LAN mode still fails, Bambu asks for a support ticket with the printer and Bambu Studio logs.

If only the camera fails

• Turn on liveview. H2, P2S and X series printers have a LAN mode liveview switch on the LAN Only page. Bambu’s guide says to turn on “LAN Only Liveview” to see the camera in Bambu Studio.
• “Missing LAN IP of printer.” Bambu Studio has not found the printer’s address. Bambu’s P1 notes trace this to firewalls that block SSDP packets (the UDP 1990 discovery broadcasts) or routers that do not forward them. Bambu says to turn off the computer’s firewall and restart Bambu Studio. If the error stays, check that port 322 or 6000 is open.
• LAN error codes. Bambu’s live view guide says -10051, -10060 and -10061 on Windows mean “something wrong with your LAN network”; on macOS and Linux the codes are -110, -111 and -112. Work through steps 2 to 7.
• Windows playback. Bambu Studio plays the stream through Windows Media Player, and error 100 means it is not installed. Install it from Windows Optional Features, then restart Bambu Studio.
• Pauses during uploads. On the P1, Bambu says video is suspended while a 3MF file uploads or downloads.

Do you need Developer Mode for LAN mode?

Not for Bambu Studio, which prints, monitors and shows the camera in normal LAN Only mode. Third-party software is different. Under Bambu Lab’s authorization firmware, starting a print from software other than Bambu Studio requires Bambu Connect. Movement, temperature, fan, AMS and calibration commands need authorized access “in both cloud mode and normal LAN mode.” Developer Mode removes those checks.

Without Developer Mode, Bambu says MQTT status pushes “for tools like Home Assistant”, SD card printing and microSD firmware updates keep working. A Home Assistant dashboard that shows status but cannot start prints or set temperatures has an authorization problem, not a network fault. Cloud mode has an older limit too. Since P1 firmware 01.06.00.00, the local MQTT broker refuses to start prints or heat the nozzle and bed while the printer is logged in to Bambu Cloud, and Bambu’s advice for Home Assistant users was LAN Only mode.

If the Developer Mode switch is missing from the LAN Only page (on P series printers, scroll down once LAN Only is on), update the firmware. Developer Mode arrived in firmware 01.08.05.00 on the X1, 01.08.02.00 on the P1, 01.05.00.00 on the A1 and A1 mini, and 01.01.00.00 on the H2D. Bambu warns that it “will open the MQTT channel, live stream, and FTP, giving you full control over your printer and its network security,” and that it “will not allow the printer to be connected to Bambu Cloud.” Setup steps are in the LAN-only guide; why Bambu added the checks is covered in the Bambu Lab firmware controversy.