Bank Account Validation 
Bank account numbers are structured according to national and international standards. In many countries, algorithms are available to check that the bank account number is correct. If this number is not checked in the system and happens to be wrong, any payment orders to this account are rejected and bank fees are charged to the company.
SAP Business One performs two types of bank account validation:
Validation of domestic bank accounts (available for all countries)
The system checks the number of digits of the following data:
Bank code
Branch
Account number
Control key
Additional country-specific validation for Belgium, France, Italy, Netherlands, Portugal, and Spain
Validation of International Bank Account Numbers (IBAN) (available for IBAN countries)
The system checks whether the IBAN is correct.
These checks are carried out when you enter new bank account information, for example, in the Banks – Setup or House Bank Accounts – Setup windows, or in the business partner master data. In addition, the checks are carried out when bank account numbers are used in the Payment Engine add-on (through the payment wizard or through Bill of Exchange management). In this case, the system verifies that the bank accounts are correct before creating the payment file. If the bank account number you entered does not comply with the default, the application displays a warning message and you can modify the information entered.
You define the parameters for bank account validation in the Countries
– Setup window under 
Administration
Setup Business Partners
Countries 
.