HL7812 ppp local ip-address not correct

IoT Modules
1

SetUp: HL7812 connected over UART,
ppp0 connection is created, and its setting is

noauth
connect "/usr/sbin/chat -v -t 5 -f /etc/chatscripts/hl78xx-chat"
debug
/dev/ttySWI2
115200
noipv6
connect-delay 30000
defaultroute
noipdefault
usepeerdns
lcp-echo-interval 20

ppp0 successfully create a connection, but the local IP address is in-correct, i.e. not able to reach internet, (example: 8.8.8.8)
it always assigns below ip address,

 inet 10.0.0.10  netmask 255.255.255.255  destination 10.0.0.1

AT+CGCONTRDP
+CGCONTRDP: 1,5,"lp.swir.mnc024.mcc208.gprs",10.124.46.70.255.255.255.252,10.124.46.69,8.8.8.8,4.2.2.2,,,,,,,,,

I expect the local ip address to be “10.124.46.70”

if I restart the pppd service, it does assign the correct IP address,

Can someone shed light on why ppp0 is not getting assigned a correct IP address the first time?

2

I don’t see problem with Ubuntu 18 to dial up with wvdial via UART interface with FW 5.5.14.0:



ati3
HL7812.5.5.14.0

OK



owner@ubuntu:~$ sudo wvdial
--> WvDial: Internet dialer version 1.61
--> Initializing modem.
--> Sending: AT
AT
OK
--> Sending: ATE0
ATE0
OK
--> Modem initialized.
--> Sending: ATDT*99***1#
--> Waiting for carrier.
CONNECT
--> Carrier detected.  Waiting for prompt.
~[7f]}#@!}!}!} }4}"}&} } } } }%}&)Inb}'}"}(}"[16]L~
--> PPP negotiation detected.
--> Starting pppd at Mon Jan 13 12:34:44 2025
--> Pid of pppd: 8246
--> Using interface ppp0
--> local  IP address 10.84.176.208
--> remote IP address 10.0.0.1
--> primary   DNS address 10.13.168.152
--> secondary DNS address 10.13.200.152

************************


owner@ubuntu:~$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=117 time=183 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=117 time=151 ms

--- 8.8.8.8 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1002ms
rtt min/avg/max/mdev = 151.921/167.905/183.890/15.989 ms
owner@ubuntu:~$ ifconfig ppp0
ppp0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 10.84.176.208  netmask 255.255.255.255  destination 10.0.0.1
        ppp  txqueuelen 3  (Point-to-Point Protocol)
        RX packets 52  bytes 9756 (9.7 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 63  bytes 9038 (9.0 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
3

My question was specifically on why, ppp0 was getting assigned 10.0.0.10, which is in-correct local address.
If I restart the pppd, it does get correct ip address.

Do we need to wait a certain amount of time before we need call pppd after modem initialization?

4

i don’t know why, it seems it only happens on your platform
Have you tried other linux platform like Ubuntu 18?

5

What is the pppd version running on your platform with Ubuntu 18?

6 
owner@ubuntu:~$ /usr/sbin/pppd --version
pppd version 2.4.7
7

I do not think the issues is with pppd, as this IP address is coming from the modem,
check image below

image
image1167×630 180 KB

8

it seems it only happens on your platform
Have you tried other linux platform like Ubuntu 18?