Posted: Sun Aug 18, 2024 10:26 Post subject: Is WireGuard supported on TL-WR740N?
I have ancient TL-WR740N v4 which has only 4MB flash and 32MB RAM.
However, WireGuard on that model doesn't seem to work. I'm running latest r57956 build.
After configuring WG tunnel under Setup > Tunnels and rebooting
Code:
Jan 1 02:00:08 dd-wrt user.info : [httpd] : successfully started
Jan 1 02:00:09 dd-wrt user.info root: Enable WireGuard interface oet1 on port 51820
Jan 1 02:00:09 dd-wrt user.notice eop-tunnel.prewall[818]: Unable to modify interface: Protocol not supported
Jan 1 02:00:09 dd-wrt user.notice eop-tunnel.prewall[818]: Unable to modify interface: Protocol not supported
Jan 1 02:00:10 dd-wrt user.err root: ERROR: WireGuard no valid IPv4 or IPV6 tunnel address for oet1: , please correct, trying the old way
Jan 1 02:00:10 dd-wrt user.info : [sfe] : shortcut (SFE) forwarding engine successfully started
Jan 1 02:00:11 dd-wrt user.info root: WireGuard acquiring /tmp/oet-raip.lock for raip 1057
Jan 1 02:00:11 dd-wrt user.info root: WireGuard /tmp/oet-raip.lock acquired for raip 1057
Jan 1 02:00:12 dd-wrt user.info : [sfe] : shortcut (SFE) forwarding engine successfully started
When I look under Setup > Networking then oet1 interface does not show up there at all.
After quick search I found few threads around the internet mentioning WireGuard requires at least 8MB flash space.
I'm confused because if true - why my device has WireGuard option available at all?
Do I have too big expectations?
Joined: 18 Mar 2014 Posts: 13879 Location: Netherlands
Posted: Sun Aug 18, 2024 10:55 Post subject:
WireGuard guides are a sticky in the Advanced Networking forum.
From the Client setup guide:
Quote:
WireGuard is usually available on routers with 8 MB Flash RAM or more (there are a few exceptions) and using at least Kernel 3.10 (so not on K2.6 builds).
If you are running K3.10 yours might be an exception
Although this does not bode well:
Quote:
Jan 1 02:00:09 dd-wrt user.notice eop-tunnel.prewall[818]: Unable to modify interface: Protocol not supported
This router indeed has kernel 3.10, but I'm not too hopeful due to low flash space and systlog errors.
Just hoped someone can share their first hand experience or provide hints how to verify.
Posted: Tue Jan 20, 2026 8:54 Post subject: WireGuard not fully supported on TL-WR941NDv3 also
Hi, necropost, but its still actual question .
I have TL-941NDv3 router (also 4/32 model) with the latest dd-wrt on it(v3.0-r63391 std). WireGuard is onboard as all menus and commands are there, but it doesn't work as it should.
Syslog shows wireguard activity with tries to create interface, add routes, firewall policies and the same errors as mentioned
Quote:
user.notice eop-tunnel.prewall[]: Unable to modify interface: Protocol not supported
but also I found an issue with wireguard module.
If you do modprobe wireguard:
Posted: Fri Jan 23, 2026 19:01 Post subject: WireGuard works like a charm now on TL-941NDv3
hi
At first I should say much appreciated BrainSlayer and all devs work!
TL-941NDv3 and some routers that use 3.10 kernel (including topic starter's TL-740ND) are now able to use WireGuard!
Now about "poor" performance mentioned in some post on dd-wrt forum (expected not more than 5Mbps)
My router is configured as POC to provide known WiFi at some new place with WiFi access (like hotel) via VPN to ISP (WireGuard) so its the most heavy scenario as it has WISP+AP+WireGuard VPN (as mentioned its a ProofOfConcept not live to test stability and performance).
so
System Details
CPU Model: Atheros AR9132 rev 2 (0xb9)
CPU Cores: 1
CPU Features: MIPS32r1 MIPS32r2 MIPS16
CPU Clock: 400 Mhz (304)
Dhrystones: 440.52 DMIPS
Speedtest results to different country via WireGuard over WISP:
Quote:
Latency: 38ms
Download: 18Mbps
Upload: 21Mbps
1 client in routers WiFi and several clients in WISP
Load Average at routers GUI sometimes climbed to 74% while test was running (done about 10 tests).
Will do more tests later with router connected by WAN port with cable providing WiFi to clients.
Posted: Wed Jan 28, 2026 11:18 Post subject: WireGuard works, but not like a charm :)
hi
Not sure if its interesting to anyone and if it will be treated as issue to be fixed , but my experience after some time of using WireGuard as VPN to ISP(default route): I can say that its not stable.
As I mentioned before I did tests for bandwidth and thought that issues are due to low power of CPU (router TL-941NDv3 even rebooted sometimes).
Later after some days of rest I tried WG via ISP with online FM radio - not much traffic, but constant. I encountered dips in stream after some time (30+sec), sometimes it stopped totally and required to restart stream or change station.
Also there were couple reboots of router on its own. Load Average was always low not more than 20%.
Tried the same scenario with WireGuard tunnel disabled - router was online without any issues for a week or so with sometimes enabled the same stream of online FM radios - no any dips or stops at all during hours.
Now I updated firmware to the latest published (DD-WRT v3.0-r63485 std (01/25/26))- all the same with WireGuard enabled/disabled.
Also, suppose its an issue - no firewall rules present (just the ones I added manually via firewall commands as Security/Firewall and Administration/Management/Remote Access has no effect)?
iptables -nvL:
Chain FORWARD (policy ACCEPT 6108 packets, 3133K bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 10977 packets, 2463K bytes)
pkts bytes target prot opt in out source destination
/tmp/.ipt has rules as it should.
Thanks
Update
Reconfigured WireGuard to another ISP VPN (default route), firmware was not updated (DD-WRT v3.0-r63485 std (01/25/26)) and after 6 hours of uptime with constant online FM playback with WG enabled I can say it works like a charm no any dips or stops.
So it seems just missing firewall rules is an issue.
Much appreciated BrainSlayers and devs work!
Last edited by feodim on Sat Jan 31, 2026 15:28; edited 3 times in total
Joined: 06 Jun 2006 Posts: 7824 Location: Dresden, Germany
Posted: Thu Jan 29, 2026 23:20 Post subject:
numerci wrote:
I wander how come that Wireguard is present on WRT740N and not on Archer C7. The first has less memory and less storage.
it is present on archer c7 is the the correct answer. go to setup->tunnels and just configure it _________________ "So you tried to use the computer and it started smoking? Sounds like a Mac to me.." - Louis Rossmann https://www.youtube.com/watch?v=eL_5YDRWqGE&t=60s
@kernel-panic69 its 4/32 device on diet. There is no nft no IPv6 etc in favor of WireGuard that is amazing decision (kill feature as for me)! Maybe in future honored BrainSlayer and devs will replace some more packages to add IPv6 if its possible at all
Posted: Mon Feb 02, 2026 8:45 Post subject: iptables based firewall issue on 4/32 devices?
hi
TL-WR941NDv3 with WireGuard based default route uptime is 2 days (whole weekend) - no issues so far!
I tried to manually restore iptables from /tmp/.ipt file and it failed, so missing firewall policies could be caused by that:
