cec – Coraid Ethernet Console


cec [ -dp ] [ -S srv ] [ -c esc ] [ -e ea ] [ -h host [ -s shelf ] [ interface ]


Cec uses raw Ethernet packets to connect to a CEC server for console access. All clients share the same session. Coraid appliances and Coraid Plan 9 kernels can currently be CEC servers.

Cec starts by probing the specified network interface for available CEC servers. The default is /net/ether0. Only one cec process may be run per Ethernet interface. If the server is specified with the -b, -h, or -s options, communication will proceed immediately upon discovery of the first CEC server with the specified address. Otherwise, a selection prompt will be displayed showing the discovered CEC servers available for communication. Unless the -p option is specified, cec exits if no matching servers are found. The selection prompt accepts


Connect to server number (from the first column),  


Probe the interface again, and  



Note the selection number is not the shelf address but the cec-generated sequence number printed in the leftmost column.

Once connected to a CEC server, typing the escape character will drop the user into an escape prompt where the user may type q to quit the connection, i to send the escape character across the connection, or . to continue the connection.



Set the escape character to control-esc. The default setting is control-\.  


Print debugging information.  


Connect to the server with Ethernet address ea; implies -p.  


Connect to the server host. Note that this name might not be the same as the contents of /dev/sysname on the target system.  


Persist: continue trying to connect even if there are no matching servers. This is useful when connecting to a CPU server before it boots.  


Connect to the server at address shelf.  


Post the CEC connection as /srv/srv to allow sharing.  

If the -e, -s, or -h options are given, cec will exit upon closing the connection. Otherwise, cec will return to the selection prompt upon connection close.



; cec '#l1/ether1'
 0       1 003048679b89 
[#qp]: 0

SR shelf 1> 
SR shelf 1> >>> q
 0       1 003048679b89 
[#qp]: q




The CEC protocol should be integrated with the console server. The arbitration between the keyboard and network is suboptimal.

Early boot information and very late crash information from servers may be lost due to timing quirks.