Not working on UDM-SE

[chrisdooks]

UniFi OS UDM SE 2.5.11
ISP - Aquiss FTTP 900 Mbps
PPPoE authentication, no VLAN

Extract from history, last attempted ~ 2100 UK time, 10/10/2022:

mkdir -p /mnt/data/change-ppp-mtu
curl -Lo /mnt/data/on_boot.d/10-monitor-ppp-mtu.sh https://raw.githubusercontent.com/TotalGriffLock/udmp-jumbo-frames-ppp/main/10-monitor-ppp-mtu.sh
curl -Lo /mnt/data/change-ppp-mtu/11-change-ppp-mtu.sh https://raw.githubusercontent.com/TotalGriffLock/udmp-jumbo-frames-ppp/main/11-change-ppp-mtu.sh
chmod +x /mnt/data/on_boot.d/10-monitor-ppp-mtu.sh
chmod +x /mnt/data/change-ppp-mtu/11-change-ppp-mtu.sh
/mnt/data/on_boot.d/10-monitor-ppp-mtu.sh

Post execution of script, UDM SE kept showing ppp0 not found wrapping in the terminal. I left it for around 10 minutes, no change, so removed the scripts and rebooted and WAN connection back up (albeit at 1492).

ISP is on port 10 (SFP+ port).

[TotalGriffLock]

Could you try the following please, and let me know the output. The script will run forever so you'll need to Ctrl-C to get out of it once it's run for 30 seconds or so. Please kill all existing copies of the script from running first.

cd /mnt/data/change-ppp-mtu
sed "s/ > \/dev\/null//" 11-change-ppp-mtu.sh > 11-change-ppp-mtu-debug.sh
bash ./11-change-ppp-mtu-debug.sh

[chrisdooks]

Sure, here you go, sorry about the wrapping, not sure why it's not working correctly.:

bash ./11-change-ppp-mtu-debug.sh
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
Cannot find device "ppp0"
pppd: no process found
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
pppd: no process found
Cannot find device "ppp0"
Checking interfaces as no correctly configured PPP interface exists
Checking ppp0
Checking eth9
eth9 has right MTU
Cannot find device "ppp0"
Killing pppd
^C
root@UDM-SE:/mnt/data/change-ppp-mtu# Cannot find device "ppp0"
Cannot find device "ppp0"

[TotalGriffLock]

Ok, weird. Can you send the output this please, you can obfuscate out the IP addresses, I don't need to know those

ip link list

[chrisdooks]

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 72:a7:41:68:a7:da brd 00:00:00:00:00:00
2: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 76:8a:24:d3:0f:18 brd ff:ff:ff:ff:ff:ff
3: eth9: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 10000
    link/ether 70:a7:41:68:a7:e3 brd ff:ff:ff:ff:ff:ff
4: eth10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc mq master br0 state UP mode DEFAULT group default qlen 10000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
5: switch0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 9216 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether 72:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
6: gre0@NONE: <NOARP> mtu 1476 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/gre 0.0.0.0 brd 0.0.0.0
7: gretap0@NONE: <BROADCAST,MULTICAST> mtu 1462 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
8: erspan0@NONE: <BROADCAST,MULTICAST> mtu 1450 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
9: ip_vti0@NONE: <NOARP> mtu 1480 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ipip 0.0.0.0 brd 0.0.0.0
10: sit0@NONE: <NOARP> mtu 1480 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/sit 0.0.0.0 brd 0.0.0.0
11: eth8: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc htb state DOWN mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e2 brd ff:ff:ff:ff:ff:ff
12: ifb0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc htb state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 46:a7:54:f4:f5:14 brd ff:ff:ff:ff:ff:ff
13: ifb1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 32
    link/ether d2:1b:f8:fa:c1:bd brd ff:ff:ff:ff:ff:ff
14: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 72:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
15: eth0@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:da brd ff:ff:ff:ff:ff:ff
16: eth1@switch0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
17: eth2@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:dc brd ff:ff:ff:ff:ff:ff
18: eth3@switch0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:dd brd ff:ff:ff:ff:ff:ff
19: eth4@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:de brd ff:ff:ff:ff:ff:ff
20: eth5@switch0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:df brd ff:ff:ff:ff:ff:ff
21: eth6@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e0 brd ff:ff:ff:ff:ff:ff
22: eth7@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e1 brd ff:ff:ff:ff:ff:ff
23: eth10.2@eth10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br2 state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
24: eth10.3@eth10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br3 state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
25: eth10.4@eth10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br4 state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
26: eth10.72@eth10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br72 state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
27: eth10.85@eth10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br85 state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
28: switch0.1@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br0 state UP mode DEFAULT group default qlen 1000
    link/ether 72:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
29: switch0.2@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br2 state UP mode DEFAULT group default qlen 1000
    link/ether 72:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
30: switch0.3@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br3 state UP mode DEFAULT group default qlen 1000
    link/ether 72:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
31: switch0.4@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br4 state UP mode DEFAULT group default qlen 1000
    link/ether 72:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
32: switch0.72@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br72 state UP mode DEFAULT group default qlen 1000
    link/ether 72:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
33: switch0.85@switch0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue master br85 state UP mode DEFAULT group default qlen 1000
    link/ether 72:a7:41:68:a7:db brd ff:ff:ff:ff:ff:ff
34: br2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
35: br3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
36: br4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
37: br72: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
38: br85: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9216 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 70:a7:41:68:a7:e4 brd ff:ff:ff:ff:ff:ff
39: cni0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether f2:bd:93:90:a3:b1 brd ff:ff:ff:ff:ff:ff
41: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1492 qdisc htb state UNKNOWN mode DEFAULT group default qlen 3
    link/ppp

[TotalGriffLock]

Did you say you get the same error if you run the command manually? e.g.

ip link set ppp0 mtu 1500

[chrisdooks]

I tried something similar to the below:

sed -i 's/1492/1500/g' /etc/ppp/peers/$PPP_IFACE
ifconfig $PPP_IFACE mtu 1500
ifconfig $WAN_IFACE mtu 1508

Matching my setup, but I always had a loop with the ppp interface not appearing, and when it did and I got WAN connectivity again I didn't pass any tests for 1500 bytes.

[TotalGriffLock]

I assume you've not changed the start of the file where it says this:

MINTERFACES="(ppp0)"

I'll see if I can grab you on Discord later today and run through some more tests if that works

[chrisdooks]

Yeah, I haven't made any changes to the sh files.

Did you get to the bottom of this?

Also get the same thing on a UDM SE 2.5.11, pppoe on vlan10

[chrisdooks]

No, not yet. We were debugging it but haven't got to the bottom of it so far.

[llaforest]

Great, also in the same boat with my UDM SE 2.5.11 with ISP on port 10. Having some packets lost sometimes, so I thought this could help resolve those.

[TotalGriffLock]

If you guys are still experiencing issues please use the debug version of the script on here and let me know how you get on.

[bdavj]

Unfortunately this seems to have stopped working on UDM-SE again, it seems to be setting the PPP interface MTU to 1500, but for some reason the Ethernet interface reverts back to 1500, which makes a bit of a mess of SSL connections.

Going to do some digging when I have a moment and will submit a PR if I can work it out.