ESXi 8.0 formats syslog messages in compliance with either RFC 3164 or RFC 5424.
Note: The timestamps associated with RFC 3164 messages are in RFC 3339 format, an exception to the RFC 3164 specification.
The definition of the ESXi transmission formats for RFC 3164 and RFC 5424 is in Augmented Backus-Naur Form (ABNF).
RFC 3164 Transmission Message Format
| Parameter | Value |
| SYSLOG-MSG | HEADER SP MSG |
| HEADER | PRI TIMESTAMP SP HOSTNAME SP APP-NAME [PROC-IDENTIFIER] ":" |
| PRI | "<" PRIVAL ">" |
| PRIVAL | 1*3DIGIT ; range 0 .. 191 (the MSG PRI; contains facility and severity values, ORed together) |
| APP-NAME | 1*32PRINTUSASCII |
| HOSTNAME | 1*255PRINTUSASCII |
| PROC-IDENTIFIER | "[" *DIGITS "]" ; the PID associated with APP-NAME |
| TIMESTAMP | FULL-DATE "T" UTC-TIME (Never set a TIME-OFFSET) |
| FULL-DATE | DATE-FULLYEAR "-" DATE-MONTH "-" DATE-MDAY |
| DATE-FULLYEAR | 4DIGIT |
| DATE-MONTH | 2DIGIT ; 01-12 |
| DATE-MDAY | 2DIGIT ; 01-28, 01-29, 01-30, 01-31 based on month/year |
| UTC-TIME | TIME-HOUR ":" TIME-MINUTE ":" TIME-SECOND [TIME-SECFRAC] "Z" |
| TIME-HOUR | 2DIGIT ; 00-23 |
| TIME-MINUTE | 2DIGIT ; 00-59 |
| TIME-SECOND | 2DIGIT ; 00-59 |
| TIME-SECFRAC | "." 1*6DIGIT |
| STRUCTURED-DATA | 1*SD-ELEMENT |
| SD-ELEMENT | "[" SD-ID *(SP SD-PARAM) "]" |
| SD-PARAM | PARAM-NAME "%d34 PARAM-VALUE %d34 |
| SD-ID | SD-NAME |
| PARAM-NAME | SD-NAME |
| PARAM-VALUE | UTF-8-STRING ; characters '"', '\' and ']' MUST be escaped. |
| SD-NAME | 1*32PRINTUSASCII ; except '', SP, ']', %d34 (") |
| MSG | [STRUCTURED-DATA SP] UTF-8-STRING |
RFC 5424 Transmission Message Format
| Parameter | Value |
| SYSLOG-MSG | HEADER SP STRUCTURED-DATA [SP MSG] |
| HEADER | PRI VERSION SP TIMESTAMP SP HOSTNAME SP APP-NAME SP PROCID SP MSGID |
| PRI | "<" PRIVAL ">" |
| PRIVAL | 1*3DIGIT ; range 0 .. 191; contains facility and severity data |
| VERSION | NONZERO-DIGIT 0*2DIGIT |
| HOSTNAME | 1*255PRINTUSASCII |
| APP-NAME | 1*48PRINTUSASCII |
| NILVALUE | '-' |
| PROCID | NILVALUE | *DIGITS ; the PID associated with APP-NAME |
| MSGID | NILVALUE |
| TIMESTAMP | FULL-DATE "T" UTC-TIME |
| FULL-DATE | DATE-FULLYEAR "-" DATE-MONTH "-" DATE-MDAY |
| DATE-FULLYEAR | 4DIGIT |
| DATE-MONTH | 2DIGIT ; 01-12 |
| DATE-MDAY | 2DIGIT ; 01-28, 01-29, 01-30, 01-31 based on month/year |
| UTC-TIME | TIME-HOUR ":" TIME-MINUTE ":" TIME-SECOND [TIME-SECFRAC] "Z" |
| TIME-HOUR | 2DIGIT ; 00-23 |
| TIME-MINUTE | 2DIGIT ; 00-59 |
| TIME-SECOND | 2DIGIT ; 00-59 |
| TIME-SECFRAC | "." 1*6DIGIT |
| STRUCTURED-DATA | NILVALUE / 1*SD-ELEMENT |
| SD-ELEMENT | "[" SD-ID *(SP SD-PARAM) "]" |
| SD-PARAM | PARAM-NAME " %d34 PARAM-VALUE %d34 |
| SD-ID | SD-NAME |
| PARAM-NAME | SD-NAME |
| PARAM-VALUE | UTF-8-STRING ; characters '"', '\' and ']' MUST be escaped. |
| SD-NAME | 1*32PRINTUSASCII ; except '', SP, ']', %d34 (") |
| MSG | MSG-UTF8 |
| MSG-UTF8 | BOM UTF-8-STRING |
| BOM | %xEF.BB.BF |
