| UUinbln | IN-Berlin UUCP |
| Unetmbx | 0000-uucp(0000) |
| Urizano | Andreas Hoppe |
| Utmpmbx | tmpmbx uucp |
| Uuropax | 0000-uucp(0000) |
| ubr :-) | Ulrich Brochhagen |
| udo | Udo Schuetzler |
| udok | Udo Klockenkaemper |
| ulf | Ulf Schoeneberg |
| untergrund | untergrund |
| update | Update |
| user | Internationale Stadt User-Beratung |
| uta | Uta Schaegerl |
| uwel | Uwe Ludwig |
| uwes | Uwe Schmidt |
