This is useful to be able to quickly identify which element of the site is slow to load. This will show both the timestamps at the beginning of the time and also the execution time at the end of the line. You can enable timestamps within the strace output. Some basic examples of how I use it are below: It basically captures and records all system calls made by a process and the signals received by the process. Strace is a tool for debugging and troubleshooting programs. * Connected to 1.1.1.1 (1.1.1.1) port 25 (#0) Posted on DecemCategories System Administration strace Cheat Sheet Below is an example for checking if you can connect to port 25 on the remote server: ~]# curl -v telnet://1.1.1.1:25 You can tell the connection failed as the command will hang or return an error about ‘connection refused’.Īnother way around this is to use curl if it is available. ![]() ![]() The example below shows connections that succeed since they return instantly: ~]# echo > /dev/tcp/1.1.1.1/80 While that is proof in and of itself, what if you needed something more for some reason?Īssuming you have root access and ‘telnet’ or ‘nc’ is not installed, you can use the bash networking features (see REDIRECTION man page). rackspace-monitoring-agent-plugins-contribĮver hop onto a server where the network admin may have been a bit over-caffeinated when they were locking down the firewall? What if they also locked down egress along with ingress? They want you to prove you cannot connect outbound, but you cannot even install ‘telnet’ or ‘nc’ since yum/apt can’t get outbound.Search Search for: Archives Archives Categories
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