Nmap offers 6 timing templates which can be specified with -T option and their number from 0-to-5 or their name. The following -T0 as the slowest and -T5 as the fastest. These timing templates in nmap are used to optimize and improve the quality and performance of the scan to get the desired results.
Timing templates and their effects:
T0 | T1 | T2 | T3 | T4 | T5 | |
Name | Paranoid | Sneaky | Polite | Normal | Aggressive | Insane |
--min-rtt-timeout | 100 ms | 100 ms | 100 ms | 100 ms | 100 ms | 50 ms |
--ma-rtt-timeout | 5 minutes | 15 seconds | 10 seconds | 10 seconds | 1250 ms | 300 ms |
--initial-rtt-timeout | 5 minutes | 15 seconds | 1 second | 1 second | 500 ms | 250 ms |
--max-retries | 10 | 10 | 10 | 10 | 6 | 2 |
Initial (and minimum) scan delay (--scan-delay) | 5 minutes | 15 seconds | 400 ms | 0 | 0 | 0 |
Maximum TCP scan delay | 5 minutes | 15000 | 1 second | 1 second | 10 ms | 5 ms |
Maximum UDP scan delay | 5 minutes | 15 seconds | 1 second | 1 second | 1 second | 1 second |
--host-timeout | 0 | 0 | 0 | 0 | 0 | 15 minutes |
--script-timeout | 0 | 0 | 0 | 0 | 0 | 10 minutes |
--min-parallelism | Dynamic, not affected by timing templates | |||||
--max-parallelism | 1 | 1 | 1 | Dynamic | Dynamic | Dynamic |
--min-hostgroup | Dynamic, not affected by timing templates | |||||
--max-hostgroup | Dynamic, not affected by timing templates | |||||
--min-rate | No minimum rate limit | |||||
--max-rate | No maximum rate limit | |||||
--defeat-rst-ratelimit | Not enabled by default |
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