Siemens SIMATIC S7 System Manual page 410

Communication
8.4 Ethernet
To enter or change IP information, perform the following:
● If not already checked, click the "IP address data is fixed to the values below and cannot
be changed by other means" checkbox. The Ethernet port IP information fields are
enabled.
● Enter or change the following IP information:
– IP address
– Subnet mask
– Default gateway
– Station name
410
Note
The Station Name follows the standard DNS (Domain Name System) naming
conventions. The S7-200 SMART CPUs limit the Station Name to a maximum of 63
characters. The Station Name can consist of the lower case letters a through z, the
digits 0 through 9, the hyphen character (minus sign), and the period character.
Certain names are not allowed and this can depend on the tool used to set the Station
Name. The Station Name must not have the format "n.n.n.n" where n is a value of 0
through 999. The Station Name cannot begin with the string "port-nnn" or the string
"port-nnn-nnnnn" where "n" is a digit 0 through 9 (for example, "port-123" and "port-
123-45678" are illegal). The Station Name cannot start or end with the hyphen or
period.
System Manual, V2.3, 07/2017, A5E03822230-AF
S7-200 SMART