| Description |
This article describes a known-issue with VRRP on the FortiGate where the Advertisement Interval field (aka ‘adv-interval’) in the VRRP packet header is not being set correctly. |
| Scope | FortiGate v7.6.x. |
| Solution |
Before v7.6, VRRP’s Advertisement Interval was seconds-based and could be set from 1 to 255 seconds. In FortiOS 7.6.0 and later, VRRP was enhanced to allow the VRRP Advertisement Interval to be set in milliseconds (250 to 255000), which aligns with VRRP Version 3’s support for millisecond timers (see also: FortiGate 7.6 New Features – VRRP hello timer in milliseconds).
However, an issue currently exists where these millisecond timers are not correctly converted back to whole seconds when using the original VRRP Version 2. This can cause VRRP peerings to fail to establish due to mismatched timers. Below is an example where the adv-interval is set to 2000, and the conversion is not correct as advertised in the packet capture.
This issue is tracked as part of Known Issue 1166008, and it will be resolved in v7.6.4 and the upcoming v8.0. |
