Problem

In some cases, the uptime displayed in the Site24x7 console may not match the actual uptime shown in the device terminal (via SSH/Telnet). This can lead to confusion, especially for devices that have been running continuously for long periods.

Root cause

Site24x7 retrieves device uptime using the standard SNMP object:

sysUpTime from RFC1213-MIB

This value has a technical limitation:

• sysUpTime is stored as a 32-bit integer.
• Maximum value: 4,294,967,295 timeticks.
• This equals approximately 497 days.
• After reaching this limit, the counter rolls over and resets to zero.

What this means

If a device has been running for more than ~497 days (for example, three–five years):

• The sysUpTime counter would have reset multiple times.
• Site24x7 can only read the current cycle value.
• Hence, the uptime shown in Site24x7 will be lower than the actual device uptime.

Example

• Device actual uptime (from CLI): five years.
• SysUpTime value currently shows: 474 days.
• In ~23–24 days, the counter will reset again to zero.

This is expected behavior due to the SNMP data type limitation.

Additional consideration: SNMP agent restart

The sysUpTime value also resets when the SNMP agent on the device restarts, even if the device itself was not rebooted.

In such cases:

• Terminal uptime (SSH/Telnet) continues correctly
• SNMP-based uptime (used by Site24x7) resets

This can also cause a mismatch between actual uptime and reported uptime.

Is this a Site24x7 issue?

No. This is a known and documented limitation of SNMP (RFC1213-MIB) and applies to all monitoring tools that rely on sysUpTime.

Site24x7 is accurately reporting the value provided by the device via SNMP.

Recommendations

• For long-running devices (> one year), treat SNMP uptime as:
  • A relative indicator, not absolute lifetime uptime
• Use CLI/terminal uptime for:
  • Audits
  • Compliance reports
  • Root cause analysis
• Use SNMP uptime in Site24x7 for:
  • Detecting recent reboots
  • Monitoring availability trends
  • Alerting on unexpected restarts

Summary

This behavior is by design and is a standard SNMP limitation, not a data accuracy issue in Site24x7.