Overview
ping, traceroute and mtr are the everyday tools for checking whether a host is reachable and where along the path problems occur. This article explains how to use each one and how to interpret the results when diagnosing a Pod.
ping
ping sends ICMP echo requests and reports round-trip time and packet loss.
bash
ping -c 5 1.1.1.1
ping -c 5 alypod.com
ping -6 -c 5 2606:4700:4700::1111
- 0% packet loss, steady times: the path is healthy.
- Timeouts replies: a router is simply not answering ICMP; this is normal and not necessarily a fault.
- High or jittery times: congestion or a long path.
Note that some servers and firewalls block ICMP entirely, so a failed ping does not always mean the host is down. Always test the actual service too (curl, nc, or your app).
traceroute
traceroute lists every router between you and the destination, showing where delay or loss begins.
bash
traceroute alypod.com
traceroute -T -p 443 alypod.com # TCP probe, useful when ICMP is filtered
On Windows the equivalent is tracert.
mtr
mtr combines ping and traceroute and refreshes continuously, which makes intermittent loss much easier to spot.
bash
mtr alypod.com
mtr -rwzbc 100 alypod.com
The -rwzbc 100 options run a report, send 100 packets, show hostnames and produce a text summary suitable for a support ticket.
Interpreting results
- Loss that appears at one hop and continues to the end usually indicates the problem is at or after that hop.
- Loss at a single middle hop that disappears afterwards is often just that router deprioritising ICMP — not a real fault.
- Loss that starts at the destination means your Pod or its firewall is dropping packets.
Practical example
If a Pod is unreachable over SSH but mtr shows no loss up to the Pod's IP, the network is fine and the problem is the SSH service or a firewall rule. See the connectivity troubleshooting article for the full checklist.
Related articles
- [Troubleshooting network connectivity]
- [Understanding the ALYPOD network and datacenters]
