To show debug message on telnet/ssl session:

terminal monitor

Common commands to troubleshoot sip:

debug ccsip: This has various options,

  • debug ccsip all:  This command enables all ccsip type debugging. This debug command is very active, you should use it sparingly in a live network
  • debug ccsip calls: This command displays all SIP call details as they are updated in the SIP call control block. You can use this debug command to monitor call records for suspicious clearing causes.
  • debug ccsip errors: This command traces all errors that are encountered by the SIP subsystem.
  • debug ccsip events: this command traces event, such as call setups, connections and disconnections. An events version of a debug command is often the best place to start because detailed debugs provide much useful information.
  • debug ccsip info: This command enables tracing of general SIP security parameter index (SPI) information, including verification that call redirection is disabled.
  • debug ccsip media: This command enables tracing of SIP media streams
  • debug ccsip messages: This command shows the headers of SIP messages that are exchanged between a client and a server.
  • debug ccsip preauth: This command enables diagnostic reporting of authentication, authorization, accounting (AAA) for SIP calls.
  • debug ccsip states: This command displays the SIP states and state changes for sessions within the SIP subsytem.
  • debug ccsip transport: This command enables tracing the SIP transport handler and the TCP or UDP process

show the SIP register status, and the SIP trunk lines too

UC560#show sip-ua register status
Line             peer       expires(sec)      registered     P-Associ-URI
===============  ========== ============      ==========     ============
613xxxxxxxx      -1         1750               yes
disable debugging:

no debug all