Hello,
The IP address says almost nothing about the device to which it is assigned. Apart from applications that use special addresses (like routing protocols and similar), the IP address is configurable by administrator and the same IP address can be moved from PC to a Cisco box so there is no indication possible.
However, though also reliable, more information can be revealed by looking at the MAC address of the sender. The first three bytes are called OUI (Organizationally Unique Identifier) and they are uniquely assigned to individual manufacturers. You can use this URL to look up the OUIs and see who is the manufacturer of that network card:
http://standards.ieee.org/regauth/oui/index.shtml
Best regards,
Peter
