The Priority value is calculated by first multiplying the Facility number by 8 and then adding the numerical value of the Severity. For example, a kernel message (Facility=0) with a Severity of Emergency (Severity=0) would have a Priority value of 0. Also, a "local use 4" message (Facility=20) with a Severity of Notice (Severity=5) would have a Priority value of 165. In the PRI of a syslog message, these values would be placed between the angle brackets as <0> and <165> respectively. The only time a value of "0" follows the "<" is for the Priority value of "0". Otherwise, leading "0"s MUST NOT be used. – RFC 5424, Section 6.2.1
| Severity ➡️ | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|
| Facilities |
||||||||
| kernel (0) | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| user (1) | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
| mail (2) | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 |
| system (3) | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
| security (4) | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 |
| syslog (5) | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 |
| lpd (6) | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 |
| nntp (7) | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 |
| uucp (8) | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 |
| time (9) | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 |
| security (10) | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 |
| ftpd (11) | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 |
| ntpd (12) | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 |
| logaudit (13) | 104 | 105 | 106 | 107 | 108 | 109 | 110 | 111 |
| logalert (14) | 112 | 113 | 114 | 115 | 116 | 117 | 118 | 119 |
| clock (15) | 120 | 121 | 122 | 123 | 124 | 125 | 126 | 127 |
| local0 (16) | 128 | 129 | 130 | 131 | 132 | 133 | 134 | 135 |
| local1 (17) | 136 | 137 | 138 | 139 | 140 | 141 | 142 | 143 |
| local2 (18) | 144 | 145 | 146 | 147 | 148 | 149 | 150 | 151 |
| local3 (19) | 152 | 153 | 154 | 155 | 156 | 157 | 158 | 159 |
| local4 (20) | 160 | 161 | 162 | 163 | 164 | 165 | 166 | 167 |
| local5 (21) | 168 | 169 | 170 | 171 | 172 | 173 | 174 | 175 |
| local6 (22) | 176 | 177 | 178 | 179 | 180 | 181 | 182 | 183 |
| local7 (23) | 184 | 185 | 186 | 187 | 188 | 189 | 190 | 191 |