We deployed few of our units in Seattle US. We use [EM7455] cellular modems inside our evidence processors and SIMs (T-Mobile) are provided by the customer. Everything works fine when the SIMs are configured to use static IP. Due to the cybersecurity risk we asked customer to change SIM configuration, so it dynamically changes its IP every 24 hours. They said that they can’t do that, and they will change it to update IP address every time we establish connection to another communication tower. Unfortunately it appears that [EM7455] connects to a different tower every 2 minutes and therefore it changes IP very often and doesn’t allow us to establish remote connection to the unit via a 3rd party software.
What would I need to do to restrict IP from changing every 2 minutes, and to change every 24 hours instead? Is there an AT command to lock it to change its IP every 24 hours?
Hi dawid.szewczyk ,
Welcome you to our community.
In order to troubleshoot the issue, please perform the following steps:
-
What EM7455 firmware version are you using? If you are not in the latest firmware, please download the latest one and retry.
You can get it here AirPrime EM/MC74xx Approved FW Packages -
Provide the output of the following commands:
ATI3
AT!IMPREF?
AT!GSTATUS?
AT+COPS?
AT+CGDCONT?
AT+CGPADDR -
Provide the log file that EM7455 changes IP every 2 minutes.
Hi Donald,
Please see log with ping recorded.
OUTPUT of DC UNLOCKER:
===================================================================
DC - Unlocker 2 Client 1.00.1403
Detecting modem :
selection :
manufacturer - SierraWireless/NETGEAR
model - Auto detect (recommended)
Found Applications port COM8
Found Diagnostics port COM7
Found modem : EM7455
IMEI : 359073066352885
Serial NR. : LF013240790210
Firmware : SWI9X30C_02.33.03.00
Voice feature : disabled
SIM Lock status : unlocked
Correct lock status can be readed only without SIM card inserted
===================================================================
ATI3
Manufacturer: Sierra Wireless, Incorporated
Model: EM7455
Revision: SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30
MEID: 35907306635288
IMEI: 359073066352885
IMEI SV: 20
FSN: LF013240790210
+GCAP: +CGSM,+DS,+ES
OK
===================================================================
AT!IMPREF?
!IMPREF:
preferred fw version: 02.33.03.00
preferred carrier name: GENERIC
preferred config name: GENERIC_002.072_000
preferred subpri index: 000
current fw version: 02.33.03.00
current carrier name: GENERIC
current config name: GENERIC_002.072_000
current subpri index: 000
OK
===================================================================
AT!GSTATUS?
!GSTATUS:
Current Time: 3235Temperature: 44
Reset Counter: 107Mode: ONLINE
System mode: WCDMA PS state: Attached
WCDMA band: WCDMA 1900
WCDMA channel: 9830
GMM (PS) state:Registering NORMAL SERVICE
MM (CS) state: Wait RR LU NORMAL SERVICE
WCDMA L1 state:L1M_DCH LAC: 270C (9996)
RRC state: CONNECTING UTRAN Cell ID: 025F5E2F (39804463)
RxM RSSI C0: -90RxD RSSI C0: -106
RxM RSSI C1: — RxD RSSI C1: —
OK
===================================================================
AT+COPS?
+COPS: 0,0,“T-Mobile”,2
OK
===================================================================
AT+CGDCONT?
+CGDCONT: 1,“IP”,“b2b.static”,“0.0.0.0”,0,0,0,0
OK
===================================================================
AT+CGPADDR
+CGPADDR: 1,
OK
I created a quick batch script which check cellular modem IP every few seconds. For this I am using this command:
netsh interface ip show address “Cellular” | findstr “IP Address”
This is what I have received:
Loop 1
02/11/2021
09:33
IP Address: 169.254.165.67
Loop 2
02/11/2021
09:33
IP Address: 169.254.165.67
Loop 3
02/11/2021
09:33
IP Address: 22.34.21.230
Loop 4
02/11/2021
09:33
IP Address: 22.34.21.230
Loop 5
02/11/2021
09:33
IP Address: 169.254.165.67
Loop 6
02/11/2021
09:33
IP Address: 169.254.165.67
Loop 7
02/11/2021
09:34
IP Address: 169.254.165.67
Loop 8
02/11/2021
09:34
IP Address: 30.101.48.165
Loop 9
02/11/2021
09:34
Loop 10
02/11/2021
09:34
IP Address: 169.254.165.67
Loop 11
02/11/2021
09:34
IP Address: 169.254.165.67
Loop 12
02/11/2021
09:34
IP Address: 22.34.55.62
Loop 13
02/11/2021
09:35
Loop 14
02/11/2021
09:35
IP Address: 169.254.165.67
Loop 15
02/11/2021
09:35
IP Address: 169.254.165.67
Loop 16
02/11/2021
09:35
IP Address: 22.34.21.230
Loop 17
02/11/2021
09:35
Loop 18
02/11/2021
09:35
IP Address: 169.254.165.67
Loop 19
02/11/2021
09:36
IP Address: 169.254.165.67
Loop 20
02/11/2021
09:36
IP Address: 22.34.55.62
Loop 21
02/11/2021
09:36
IP Address: 22.34.55.62
Loop 22
02/11/2021
09:36
IP Address: 169.254.165.67
Loop 23
02/11/2021
09:36
IP Address: 169.254.165.67
Loop 24
02/11/2021
09:36
IP Address: 30.108.252.113
Loop 25
02/11/2021
09:37
IP Address: 30.108.252.113
Loop 26
02/11/2021
09:37
IP Address: 169.254.165.67
Loop 27
02/11/2021
09:37
IP Address: 169.254.165.67
Loop 28
02/11/2021
09:37
IP Address: 169.254.165.67
Loop 29
02/11/2021
09:37
IP Address: 22.34.21.230
Loop 30
02/11/2021
09:37
Loop 31
02/11/2021
09:38
IP Address: 169.254.165.67
Loop 32
02/11/2021
09:38
IP Address: 169.254.165.67
Loop 33
02/11/2021
09:38
IP Address: 22.34.55.62
Loop 34
02/11/2021
09:38
IP Address: 22.34.55.62
Loop 35
02/11/2021
09:38
Loop 36
02/11/2021
09:38
IP Address: 169.254.165.67
Loop 37
02/11/2021
09:39
IP Address: 169.254.165.67
Loop 38
02/11/2021
09:39
IP Address: 22.34.21.230
Loop 39
02/11/2021
09:39
IP Address: 22.34.21.230
Loop 40
02/11/2021
09:39
IP Address: 169.254.165.67
Loop 41
02/11/2021
09:39
IP Address: 30.108.252.113
Loop 42
02/11/2021
09:39
Loop 43
02/11/2021
09:40
IP Address: 169.254.165.67
Loop 44
02/11/2021
09:40
IP Address: 22.34.55.62
Loop 45
02/11/2021
09:40
IP Address: 22.34.55.62
Loop 46
02/11/2021
09:40
IP Address: 22.34.55.62
Loop 47
02/11/2021
09:40
IP Address: 22.34.55.62
Loop 48
02/11/2021
09:40
IP Address: 169.254.165.67
Loop 49
02/11/2021
09:41
IP Address: 169.254.165.67
Loop 50
02/11/2021
09:41
IP Address: 169.254.165.67
Loop 51
02/11/2021
09:41
IP Address: 22.34.21.230
Loop 52
02/11/2021
09:41
Loop 53
02/11/2021
09:41
IP Address: 169.254.165.67
Loop 54
02/11/2021
09:41
IP Address: 169.254.165.67
Loop 55
02/11/2021
09:42
IP Address: 22.34.55.62
Loop 56
02/11/2021
09:42
Loop 57
02/11/2021
09:42
IP Address: 169.254.165.67
Loop 58
02/11/2021
09:42
IP Address: 169.254.165.67
Loop 59
02/11/2021
09:42
Loop 60
02/11/2021
09:42
IP Address: 30.108.252.113
Loop 61
02/11/2021
09:43
Loop 62
02/11/2021
09:43
IP Address: 169.254.165.67
Loop 63
02/11/2021
09:43
IP Address: 169.254.165.67
Loop 64
02/11/2021
09:43
IP Address: 30.100.138.60
Loop 65
02/11/2021
09:43
Loop 66
02/11/2021
09:43
Loop 67
02/11/2021
09:44
IP Address: 22.34.55.62
Loop 68
02/11/2021
09:44
Loop 69
02/11/2021
09:44
IP Address: 169.254.165.67
Loop 70
02/11/2021
09:44
IP Address: 169.254.165.67
Loop 71
02/11/2021
09:44
IP Address: 22.34.89.156
Loop 72
02/11/2021
09:44
Loop 73
02/11/2021
09:45
IP Address: 169.254.165.67
Loop 74
02/11/2021
09:45
IP Address: 169.254.165.67
Loop 75
02/11/2021
09:45
IP Address: 22.34.55.62
Loop 76
02/11/2021
09:45
Loop 77
02/11/2021
09:45
IP Address: 169.254.165.67
Loop 78
02/11/2021
09:45
IP Address: 169.254.165.67
Loop 79
02/11/2021
09:46
Loop 80
02/11/2021
09:46
IP Address: 30.100.138.60
Loop 81
02/11/2021
09:46
Loop 82
02/11/2021
09:46
IP Address: 169.254.165.67
Loop 83
02/11/2021
09:46
IP Address: 169.254.165.67
Loop 84
02/11/2021
09:46
IP Address: 22.34.55.62
Loop 85
02/11/2021
09:47
Loop 86
02/11/2021
09:47
IP Address: 169.254.165.67
Loop 87
02/11/2021
09:47
IP Address: 169.254.165.67
Loop 88
02/11/2021
09:47
IP Address: 22.34.69.68
Loop 89
02/11/2021
09:47
IP Address: 22.34.69.68
Loop 90
02/11/2021
09:47
IP Address: 169.254.165.67
Loop 91
02/11/2021
09:48
IP Address: 169.254.165.67
Loop 92
02/11/2021
09:48
Loop 93
02/11/2021
09:48
IP Address: 30.100.138.60
Loop 94
02/11/2021
09:48
Loop 95
02/11/2021
09:48
IP Address: 169.254.165.67
Loop 96
02/11/2021
09:48
IP Address: 169.254.165.67
Loop 97
02/11/2021
09:49
IP Address: 169.254.165.67
Loop 98
02/11/2021
09:49
IP Address: 169.254.165.67
Loop 99
02/11/2021
09:49
IP Address: 169.254.165.67
Please see the above.
So the unit will get its IP address from the network when it attaches, it has no control over this, the network (I guess) can reassign a new IP address at will by re initiating a connection which I guess could be triggered on an EnodeB switch (which it would only know about of there was an active data connection or if it move out of the tracking area (a network defined geographic area that will contain a number of cells), but I have to say this is the first time I have ever heard of such a behaviour as it would create a huge amount of layer 3 traffic which is just going to cause congestion for no particular reason (these sorts of thing quite often highlight weaknesses in capacity of links that aren’t used that much).
Couple of points re the above.
- The IP addresses the unit is getting are hugely varied across a number of sub nets, this is unusual, I would normally expect to see a unit getting an IP address from the same sub net.
- It would be good to ask the unit directly what IP address it was receiving along with the cell ID, you can do this with the below AT commands.
at+cereg=2 //This will trigger unsolicited responses to be output from the unit every time the cell it is using switches.
at+cgpaddr=1 //This will show the IP address the unit has received from the network.
I might also suggest attaching any extensive logging as a text file so you don’t make the post really long, it just makes it more readable.
Regards
Matt
Hi Matt,
First thing, sorry for the logs, but I couldn’t upload a file because I was blocked by the system. I believe this might be due to my account being created recently.
Regarding the commands you listed, could you please advise what should I do once executing them? I assume that using Windows command line won’t server the purpose?
What could we do in this situation where IP changes so often and we can’t establish remote connection. Should try to escalate this to SIM provider? Or maybe there is a method where SIM is on a static IP and we can ‘update’ it every 24 hours from the modem perspective?
Hi dawid,
From your log file, the device registers for the WCDMA network. Please try configuring the device to register to the LTE network
AT!BAND=09
AT!RESET
Thank you very much. I will test this Today.
Do you have somewhere a list and description of bands that I could use?
Hi,
You can check the supported band device with the following commands:
AT!ENTERCND="A710"
AT!BAND=?
Please refer to page 24 in the AirPrime EM-MC74xx AT Command guide for a description of bands.
4117727 AirPrime EM-MC74xx AT Command Reference r4.pdf (1.4 MB)
Thank you very much for your support Donald. You were very helpful.