BG770A-GL PPPD IP Connection Issues

IoT Modules LPWA Module
1

Hello All,

Trying to figure out why PPPD creates a connection with remote IP as 10.0.0.1 and rejecting actual remote IP address 10.48.235.120.

I have encountered an issue where pppd consistently assigns 10.0.0.1 as the remote IP when establishing an LTE connection, despite multiple configuration changes. Even after modifying the /etc/ppp/peers/provider file with options such as noipdefault, nodefaultroute, ipcp-no-address, ipcp-accept-remote, and ipcp-accept-local, pppd still accepts 10.0.0.1 during IPCP negotiation. The LTE network provides a valid remote gateway via +CGCONTRDP, but pppd overrides it, leading to incorrect routing. This behavior persists regardless of attempts to reject the remote IP in IPCP responses, indicating that pppd may be prioritizing the peer’s proposal over configuration settings.

Any sights will be greatly appreciated.

PPPD log:

root@localhost:/etc/ppp# pppd call provider
Feb 6 18:55:13 localhost daemon.notice pppd[1715]: pppd 2.4.9 started by root, uid 0
Feb 6 18:55:14 localhost local2.info chat[1716]: abort on (NO CARRIER)
Feb 6 18:55:14 localhost local2.info chat[1716]: abort on (ERROR)
Feb 6 18:55:14 localhost local2.info chat[1716]: abort on (NO DIALTONE)
Feb 6 18:55:14 localhost local2.info chat[1716]: abort on (BUSY)
Feb 6 18:55:14 localhost local2.info chat[1716]: abort on (NO ANSWER)
Feb 6 18:55:14 localhost local2.info chat[1716]: send (ATZ^M)
Feb 6 18:55:14 localhost local2.info chat[1716]: expect (OK)
Feb 6 18:55:14 localhost local2.info chat[1716]: ATZ^M^M
Feb 6 18:55:14 localhost local2.info chat[1716]: OK
Feb 6 18:55:14 localhost local2.info chat[1716]: – got it
Feb 6 18:55:14 localhost local2.info chat[1716]: send (AT+CGDCONT=1,“IPV4V6”,“1116.mcs”^M)
Feb 6 18:55:15 localhost local2.info chat[1716]: expect (OK)
Feb 6 18:55:15 localhost local2.info chat[1716]: ^M
Feb 6 18:55:15 localhost local2.info chat[1716]: AT+CGDCONT=1,“IPV4V6”,“1116.mcs”^M^M
Feb 6 18:55:15 localhost local2.info chat[1716]: OK
Feb 6 18:55:15 localhost local2.info chat[1716]: – got it
Feb 6 18:55:15 localhost local2.info chat[1716]: send (AT+CGCONTRDP^M)
Feb 6 18:55:15 localhost local2.info chat[1716]: expect (OK)
Feb 6 18:55:15 localhost local2.info chat[1716]: ^M
Feb 6 18:55:15 localhost local2.info chat[1716]: AT+CGCONTRDP^M^M
Feb 6 18:55:15 localhost local2.info chat[1716]: +CGCONTRDP: 1,5,“11166.mcs.mnc410.mcc310.gprs”,10.48.235.119.255.255.255.252,10.48.235.120,166.216.138.41,166.216.138.42,^M
Feb 6 18:55:15 localhost local2.info chat[1716]: ^M
Feb 6 18:55:15 localhost local2.info chat[1716]: OK
Feb 6 18:55:15 localhost local2.info chat[1716]: – got it
Feb 6 18:55:15 localhost local2.info chat[1716]: send (ATD99#^M)
Feb 6 18:55:15 localhost local2.info chat[1716]: expect (CONNECT)
Feb 6 18:55:15 localhost local2.info chat[1716]: ^M
Feb 6 18:55:15 localhost local2.info chat[1716]: ATD99#^M^M
Feb 6 18:55:15 localhost local2.info chat[1716]: CONNECT
Feb 6 18:55:15 localhost local2.info chat[1716]: – got it
Feb 6 18:55:15 localhost local2.info chat[1716]: send (^M)
Feb 6 18:55:15 localhost daemon.debug pppd[1715]: Script /usr/sbin/chat -v -f /etc/ppp/lte finished (pid 1716), status = 0x0
Feb 6 18:55:15 localhost daemon.info pppd[1715]: Serial connection established.
Feb 6 18:55:15 localhost daemon.debug pppd[1715]: using channel 36
Feb 6 18:55:15 localhost daemon.info pppd[1715]: Using interface ppp0
Feb 6 18:55:15 localhost daemon.notice pppd[1715]: Connect: ppp0 ↔ /dev/ttyS0
Feb 6 18:55:16 localhost daemon.debug pppd[1715]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x823c3103> ]
Feb 6 18:55:16 localhost daemon.debug pppd[1715]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x823c3103> ]
Feb 6 18:55:19 localhost daemon.debug pppd[1715]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x823c3103> ]
Feb 6 18:55:19 localhost daemon.debug pppd[1715]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x823c3103> ]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [LCP ConfReq id=0x1 <mru 1430> <asyncmap 0x0> <magic 0xfd82e2e4> ]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [LCP ConfAck id=0x1 <mru 1430> <asyncmap 0x0> <magic 0xfd82e2e4> ]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [CCP ConfReq id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [IPCP ConfReq id=0x1 <compress VJ 0f 01> <addr 0.0.0.0>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [IPV6CP ConfReq id=0x1 ]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [IPCP ConfReq id=0x1 <compress VJ 0f 01> <addr 10.0.0.1> <ms-dns1 166.216.138.41> <ms-dns2 166.216.138.42>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [IPCP ConfRej id=0x1 <ms-dns1 166.216.138.41> <ms-dns2 166.216.138.42>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [IPV6CP ConfReq id=0x1]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [IPV6CP ConfNak id=0x1 ]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [CCP ConfReq id=0x1]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [CCP ConfAck id=0x1]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [CCP ConfRej id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [CCP ConfReq id=0x2]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [IPCP ConfNak id=0x1 <addr 10.48.235.119>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [IPCP ConfReq id=0x2 <compress VJ 0f 01> <addr 10.48.235.119>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [IPV6CP ConfAck id=0x1 ]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [IPCP ConfReq id=0x2 <compress VJ 0f 01> <addr 10.0.0.1>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [IPCP ConfAck id=0x2 <compress VJ 0f 01> <addr 10.0.0.1>]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [IPV6CP ConfReq id=0x2 ]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: sent [IPV6CP ConfAck id=0x2 ]
Feb 6 18:55:21 localhost daemon.notice pppd[1715]: local LL address fe80::6cfc:5095:2e13:f2ab
Feb 6 18:55:21 localhost daemon.notice pppd[1715]: remote LL address fe80::a920:91fe:5734:7476
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [CCP ConfAck id=0x2]
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: rcvd [IPCP ConfAck id=0x2 <compress VJ 0f 01> <addr 10.48.235.119>]
Feb 6 18:55:21 localhost daemon.notice pppd[1715]: local IP address 10.48.235.119
Feb 6 18:55:21 localhost daemon.notice pppd[1715]: remote IP address 10.0.0.1
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: Script /etc/ppp/ip-up started (pid 1719)
Feb 6 18:55:21 localhost daemon.debug pppd[1715]: Script /etc/ppp/ip-up finished (pid 1719), status = 0x0

Thanks,
Nitesh

2

Is it a private network?
For normal SIM card, we would not care about the remoteIP or DestinationIP.
It seems it is set inside the module.

3

Maybe you can add the options with noremoteip and there you will not see the remoteip.

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4

Thank you for your feedback.

Question is why the module does not offer actual default gateway from the provider when pppd request in IPCP?

When pppd sends the request:
sent [IPCP ConfReq id=0x1 <compress VJ 0f 01> <addr 0.0.0.0>]
and received:
rcvd [IPCP ConfReq id=0x1 <compress VJ 0f 01> <addr 10.0.0.1> <ms-dns1 166.216.138.41> <ms-dns2 166.216.138.42>]

Is there a way to debug the module?

5

As I know, actually the provider never send or set the gateway for the module.
The UE can only obtain the IP address and the DNS.
Please check
AT+CGCONTRDP? or AT+CGCONTRDP=1

6

Thanks for your feedback.

+CGCONTRDP does provide gw_addr:

+CGCONTRDP: 1,5,“11166.mcs.mnc410.mcc310.gprs”,10.48.235.119.255.255.255.252,10.48.235.120,166.216.138.41,166.216.138.42

apn: 11166.mcs
source_addr and subnet_mask: 10.48.235.119.255.255.255.252
gw_addr: 10.48.235.120

[+CGCONTRDP: ,<bearer_id>,[,<source_addr and subnet_mask>[,<gw_addr>[,<DNS_prim_addr>[,<DNS_sec_addr>[,<P-CSCF_prim_addr>[,<P-CSCF_sec_addr>[,<IM_CN_Signalling_Flag>[,<LIPA_indication>]]]]]]]]] [+CGCONTRDP: ,<bearer_id>,[,<source_addr and subnet_mask> [,<gw_addr>[,<DNS_prim_addr>[,<DNS_sec_addr>[,<P-CSCF_prim_addr>[,<P-CSCF_sec_addr>[,<IM_CN_Signalling_Flag>[,<LIPA_indication>]]]]]]]] […]]

thoughts?

7

If you must need the gateway I think you can just set the gateway as you expected.
But PPP do not care about the gaway. It transfer in NOARP packet.
If you must need the gateway I think you can try the usbnet with 4G or 5G module.