Punycode encodes international domain names into ASCII. Learn why it appears and what it means for email systems.
Punycode is an encoding used to represent internationalized domain names in ASCII so older systems can handle them. It often appears as domains starting with xn--.
In email operations, you may see Punycode in logs, authentication records, and routing. It’s normal for IDNs, but security teams monitor it closely due to spoofing potential.