| Abbreviation | Definition |
|---|---|
| IIJ | Internet Initiative Japan |
| IIOP | Internet Inter Orb Protocol |
| IKE | Internet Key Exchange |
| IKEv1 | Internet Key Exchange version 1 |
| IKEv2 | Internet Key Exchange version 2 |
| IKMN | International Knowledge Management Network |
| IKWYA | I Know Where You Are |
| ILEC | Incumbent Local Exchange Carrier |
| ILL | Internet Leased Line |
| ILMI | Interim Local Management Interface |
| IM | Instant Messaging |
| IM | Internet Messaging |
| IMAP | Internet Mail Access Protocol |
| IMAP | Internet Message Application Protocol |
| IMAP4 | Internet Mail Access Protocol V4 |
| IMC | Intelegent Management Centre |
| IMC | Inter-Machine Communication |
| IMF | Intelligent Messaging Filter |
| IMMP | Internet Message Mapping Protocol |
| IMP | Internet Mail Provider |