LTE not passing traffic

RouterOS General
1

We recently replaced an ATT SIM card in our RBLtAP-2HnD. The card is registering on the ATT network and the connection info looks solid, There is a VPN set up and the receiving router - In the log we can see something trying to connect from and ATT IP. ( the connection only happens when we restart the router). We did upgrade the firmware to 7.10.2. No other changes were made other than the actual SIM card and the OS version. We also swapped out the new card with a second new card - but no difference.

I know it’s not much information to attempt any kind of diagnosis, but any thoughts or suggested directions we should take to resolve the issue would be greatly appreciated.

2

What LTE interface are you using? How good is your signal? Are you sure that your APN is correctly configured?

Regards.

3

For AT&T, try “broadband” as APN, and disable/unchecking the “Use Network APN” in the Interface>LTE>LTE APNs. If you switched SIMs, and were using “Use Network APN”, it possible the new SIM uses some 5G APN (or something else) and the LtAP isn’t connected using the newer APN.

Might want to post the config for the LtAP.

4

All suggestions presented so far are already tried or are in place. We have tried the broadband and nxtgenphone (apn apn=NXTGENPHONE name=lte1). Again this was working until we changed out the sim card. Thanks in advance.

Here is the config

/interface bridge
add name=bridge1
/interface lte
set [ find ] name=lte1
/interface wireless
set [ find default-name=wlan1 ] ampdu-priorities=0,1,2,3,4,5,6,7 band=
2ghz-b/g/n channel-width=20/40mhz-Ce country=“united states3” disabled=no
hw-protection-mode=rts-cts hw-retries=4 installation=outdoor
max-station-count=50 mode=ap-bridge ssid=“Coba Systems Solar”
wireless-protocol=802.11 wps-mode=disabled
/interface pptp-client
add connect-to=199.189.28.102 disabled=no name=ltesolar password=*********
user=ltesolar
/interface list
add comment=defconf name=WAN
add comment=defconf name=LAN
/interface lte apn
set [ find default=yes ] apn=NXTGENPHONE name=lte1
/interface wireless security-profiles
set [ find default=yes ] authentication-types=wpa2-psk eap-methods=“” mode=
dynamic-keys supplicant-identity=MikroTik wpa2-pre-shared-key=diggers1761
/ip pool
add name=default-dhcp ranges=192.168.88.10-192.168.88.254
/ip dhcp-server
add address-pool=default-dhcp disabled=no interface=bridge1 name=defconf
/port
set 1 baud-rate=115200 name=gps
set 2 baud-rate=9600 name=usb3
/interface bridge port
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=wlan1
/ip neighbor discovery-settings
set discover-interface-list=all
/interface list member
add comment=defconf list=LAN
/ip address
add address=192.168.88.1/24 interface=bridge1 network=192.168.88.0
/ip dhcp-server network
add address=192.168.88.0/24 dns-server=8.8.8.8,8.8.4.4 gateway=192.168.88.1
ntp-server=192.43.244.18,129.6.15.28
/ip dns static
add address=192.168.88.1 comment=defconf name=router.lan
/ip firewall nat
add action=masquerade chain=srcnat out-interface=lte1
add action=dst-nat chain=dstnat comment=“Solar Controller” dst-port=8901
protocol=tcp to-addresses=192.168.88.254 to-ports=80
add action=dst-nat chain=dstnat comment=“Solar Controller SNMP” disabled=yes
dst-port=“” protocol=udp to-addresses=192.168.88.253 to-ports=161
/system clock
set time-zone-name=America/Chicago
/system gps
set port=gps
/system identity
set name=“TOPS Solar”
/tool graphing interface
add
/tool graphing resource
add

5

/interface lte apn set [ find default=yes ] apn=NXTGENPHONE name=lte1 use-network-apn=no

Mikrotik have changed the default value for use-network-apn, several times I’d like to say… In recent V7, and docs, defaults to =yes – that means “use SIM”. While you’re setting APN, it’s only used if use-network-apn**=no**

6

Tried changing the use-network-apn=no and use-network-apn=yes. There was no difference.

7

Hmm. Strange, only thing different is SIM card… AT&T normally works. It’s normally Verizon where there are issues…

Know you’ve trued but “broadband” with use-network-apn=no but that should just work to get to CGNAT internet. I can’t speak to the newer NXTGENPHONE, which may not help here since your LtAP is pretty far from 5G & that might do more IPv6 things too.

So only other thing is explicitly set the IP Type to IPV4, instead of auto or IPV4V6 in the APN profile.

I guess also, but you probably checked, the new SIM card number matches on your account?

8

To be clear: you NEED to set use-network-apn=no if you set an APN by name (e.g. broadband, etc). Otherwise, if use-network-apn=yes ANY APN set is just IGNORED and not used.