I’m using a TP-Link W9960 in bridge mode, with an OpenWrt router behind it handling the PPPoE connection to my ISP. If I initially set the TP-Link to router/PPPoE mode and then switch it to bridge mode, the OpenWrt router is able to connect successfully. However, if the connection drops due to an external issue (e.g., power outage, disconnecting the TP-Link for over 10 minutes, etc.), the OpenWrt fails to complete the PPPoE negotiation and shows the sample error below.
 

To rule out an OpenWrt-specific issue, I tested with OPNsense, another TP-Link device in router mode, and a Windows machine — all failed to establish a connection. Replacing the W9960 with a ZTE modem resolved the issue entirely.

Unfortunately, my VDSL FTTC line is quite noisy, and the ZTE modem performs poorly under those conditions, making it an impractical long-term solution.

Sat Jan 25 15:23:17 2025 daemon.notice netifd: Interface 'wan' is setting up now
Sat Jan 25 15:23:17 2025 daemon.info pppd[25413]: Plugin pppoe.so loaded.
Sat Jan 25 15:23:17 2025 daemon.info pppd[25413]: PPPoE plugin from pppd 2.4.9
Sat Jan 25 15:23:17 2025 daemon.notice pppd[25413]: pppd 2.4.9 started by root, uid 0
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]: Send PPPOE Discovery V1T1 PADI session 0x0 length 12
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]:  dst ff:ff:ff:ff:ff:ff  src d8:47:32:a3:29:05
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]:  [service-name] [host-uniq  45 63 00 00]
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]: Recv PPPOE Discovery V1T1 PADO session 0x0 length 54
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]:  dst d8:47:32:a3:29:05  src 98:03:9b:85:7b:de
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]:  [service-name] [AC-name MQATM2_A-R72A-C-EG] [host-uniq  45 63 00 00] [AC-cookie  e0 b4 9a 08 f7 65 39 44 35 3a 40 6c 80 18 6b 35]
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]: Send PPPOE Discovery V1T1 PADR session 0x0 length 32
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]:  dst 98:03:9b:85:7b:de  src d8:47:32:a3:29:05
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]:  [service-name] [host-uniq  45 63 00 00] [AC-cookie  e0 b4 9a 08 f7 65 39 44 35 3a 40 6c 80 18 6b 35]
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]: Recv PPPOE Discovery V1T1 PADS session 0x1 length 12
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]:  dst d8:47:32:a3:29:05  src 98:03:9b:85:7b:de
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]:  [service-name] [host-uniq  45 63 00 00]
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]: PADS: Service-Name: ''
Sat Jan 25 15:23:17 2025 daemon.info pppd[25413]: PPP session is 1
Sat Jan 25 15:23:17 2025 daemon.warn pppd[25413]: Connected to 98:03:9b:85:7b:de via interface eth1
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]: using channel 141
Sat Jan 25 15:23:17 2025 daemon.err tailscaled[3586]: 2025/01/25 13:23:17 magicsock: [0xc00300d8c0] derp.Recv(derp-4): derphttp.Client.Recv connect to region 4 (fra): EOF
Sat Jan 25 15:23:17 2025 kern.info kernel: [ 6049.398866] pppoe-wan: renamed from ppp0
Sat Jan 25 15:23:17 2025 daemon.info pppd[25413]: Renamed interface ppp0 to pppoe-wan
Sat Jan 25 15:23:17 2025 daemon.info pppd[25413]: Using interface pppoe-wan
Sat Jan 25 15:23:17 2025 daemon.notice pppd[25413]: Connect: pppoe-wan <--> eth1
Sat Jan 25 15:23:17 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:20 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:20 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:20 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:23 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:23 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:23 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:26 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:26 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:26 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:29 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:29 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:29 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:32 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:32 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:32 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:35 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:35 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:35 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:38 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:38 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:38 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:41 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:41 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:41 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:44 2025 daemon.debug pppd[25413]: rcvd [LCP ConfReq id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:44 2025 daemon.debug pppd[25413]: sent [LCP ConfAck id=0x1b <mru 1492> <auth pap> <magic 0x35e058a9>]
Sat Jan 25 15:23:44 2025 daemon.debug pppd[25413]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x580a89b0>]
Sat Jan 25 15:23:47 2025 daemon.warn pppd[25413]: LCP: timeout sending Config-Requests
Sat Jan 25 15:23:47 2025 daemon.notice pppd[25413]: Connection terminated.
Sat Jan 25 15:23:47 2025 daemon.notice pppd[25413]: Modem hangup
Sat Jan 25 15:23:47 2025 daemon.info pppd[25413]: Exit.