Troubleshooting·LPIC-2
Watching the wire, and telling the users
Objective 205.3 is network troubleshooting and 205.4 is notifying users. When configuration looks right and something still does not work, the packet capture is what ends the discussion. This guide captures real ICMP on the wire, explains the deadlock that killed one of these commands during authoring, and covers the two ways to tell people what is happening.
201: Networking Configuration Guide 16 of 29 Intermediate
- OSUbuntu 26.04 LTS
- Kernel7.0.0-30-generic
- systemd259
- Block devicesone 50 GB disk
- TimeAbout 17 min
| Server Name | IP Address | OS | Roles | CPU | RAM | HDD |
|---|---|---|---|---|---|---|
| LPIC2-A01 | 192.168.0.78 | Ubuntu 26.04 LTS | Primary service host - BIND, Apache, Samba, Postfix. Topic 204 RAID runs on loop devices; this machine has no spare disk | 2 Core | 4 GB | 50 GB |
This guide includes
Use this for network troubleshooting, and for telling people what is happening. This matters because a capture filtered to the connection carrying it deadlocks - which happened during authoring and is kept on the page.
- capturing three packets actually on the wire
- meeting the deadlock that killed a command during authoring
- telling the people logged in now, and the ones who log in later
Before you start
- virtual-interfaces-bridges-and-mtu
-
Three packets, actually on the wire
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The deadlock that killed a command during authoring
-
Telling people what is happening