Which of the following could indicate that your firewall is blocking SIP signaling?

The indication that your firewall may be blocking SIP signaling is evidenced by failed SIP registration attempts. When a SIP client tries to register with a SIP server, it must establish a connection that involves signaling between the client and server. If a firewall is configured incorrectly or is overly restrictive, it may block the necessary SIP packets from reaching their destination.

When SIP registration fails, it typically suggests that the signaling messages are not being successfully transmitted or received, which is a direct effect of firewall restrictions. This situation could occur if the firewall is blocking the necessary ports or protocols used for SIP communication, such as UDP or TCP on ports like 5060.

The other options, while problematic, do not specifically point to SIP signaling being blocked. For example, no internet connection could be due to several reasons unrelated to SIP, such as an outage or network misconfigurations. High latency during calls is typically an issue related to network performance rather than blocking. Unexpected call drops may stem from various issues, including network instability or issues with the SIP infrastructure but do not specifically indicate that SIP signaling is being blocked.