You have noticed an increase in SRIforSM requests coming with a GT from a phone network outside of your country which you believe could be fraudulent and you want to know if it is possible to block a GT from STP/HLR on the SMSC side. Since the SRIforSM arrives at the SMSC in the end due to the home routine, you want to add a rule to reject SRIforSMs arriving from this GT.
Yes, it is possible to block a GT on the SMSC side. To do this, follow the steps outlined below:
- Login to MGR GUI
- Go to the Routing > Routing Rules > SRISM Request menu and click Add new.
- Define a name for the new rule.
- Set the priority - it must have a priority higher than existing rules for Home-routed traffic.
- Set the SCCP CgPA condition to a GT you would like to block as per the network from which you are receiving the fraudulent traffic.
- Choose the desired Discard Action.
- Save and activate it.
Bear in mind that if the incoming SRI-SM is rejected, MT-fwSM is not received thus no CDR will be generated. However, Log records can be created if a logging profile is applied to the rule.