What is the REL file format?
The .rel extension covers two unrelated file types.
Nokia 5510 Audio - The primary use is a proprietary audio recording format native to Nokia's 5510 music phone (c. 2001). Audio files captured by the handset's built-in recorder are saved as .rel files, playable only on the originating device. The format is device-locked - an early form of hardware DRM - and is unsupported by any modern software. Later Nokia models abandoned the format in favor of open standards such as AMR and MP3.
Norton Internet Security Log File - Norton Internet Security (Symantec) also saves security logs as .rel files. These REL log files use a designated naming scheme to hint at their contents. Each REL file can be divided into two parts - iam prefix and log type - for example:
iamalert.rel- software alerts log,iamtcp.rel- TCP connection log,iamfw.rel- firewall event log.
REL log files are saved in the Norton Internet Security installation folder. Logs contain information on the type of event - be it an attack or alert - its timestamp, and other information pertaining to system response.
REL log files are generated automatically by the security program. The format was used by Symantec until around 2014, when it was superseded by Norton Security tools that use different file formats for program logs. The .rel log format is now deprecated.
Security & safety
RISK: LOWNokia .rel audio files are passive data with no executable content. The Norton .rel log files are also passive text/binary logs.
Format details
in a nutshell- Norton Internet Security Attack Log - Norton Internet Security 2001 writes IAMFW.REL and IAMALERT.REL to store firewall attack logs; these are proprietary Symantec data files, not audio.
- Nintendo Wii Relocatable Module - The Wii OS uses .rel files for relocatable code modules loaded at runtime; a completely different binary format.
Programs that open REL files
Windows1 app
Nokia 5510 handset (original device only)
Built-in Play directly on the Nokia 5510 phone - no PC software exists to open these files. Technical details
deep spec| Device compatibility (Nokia) | Nokia 5510 handset only; audio playback is locked to the phone that recorded the file |
| DRM type (Nokia) | Hardware-bound device lock; `.rel` audio files cannot be transferred and played on any other device or software |
| Encoding (Nokia) | Binary, proprietary; format is entirely undocumented with no public specification |
| Associated platform (Nokia) | Nokia Series 30/40 mobile platform (Nokia 5510, c. 2001) |
| Typical use (Nokia) | Brief voice or audio clips recorded by the Nokia 5510 built-in recorder |
| Superseded by (Nokia) | AMR (voice recording) and MP3 (music playback) on subsequent Nokia handsets |
| Modern software support | None; no desktop or mobile application can decode Nokia `.rel` audio files |
| Secondary use (Norton) | Norton Internet Security uses `.rel` for security log files (`iamfw.rel`, `iamalert.rel`, `iamtcp.rel`) - unrelated to Nokia audio |
| Norton format status | Deprecated since ~2014; replaced by Norton Security log formats when Symantec merged product lines |
| Norton file location | Saved in the Norton Internet Security installation folder on the host Windows PC |
| Released | c. 2001 (Nokia 5510) |
REL conversions
Community Q&A
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