Technical Q&A QA1339
The state of mDNSResponder


Q: Is it possible to retrieve information regarding the current internal state of mDNSResponder?

A: Yes. Starting in Mac OS X 10.3, you can send a SIGINFO signal to the mDNSResponder daemon which will cause it to output its current internal state to the system log (/var/log/system.log). This allows you to retrieve information about mDNSResponder's cached DNS resource records, and it allows you to see the active DNS Service Discovery (DNS-SD) operations. You can send the SIGINFO signal from the Terminal by typing "sudo killall -info mDNSResponder".



Listing 1. Example system.log containing mDNSResponder state info.

mDNSResponder-58.4 (Jan 28 2004 16:31:36) ---- BEGIN STATE LOG ----

Active:   PTR  en1     26 _ftp._tcp.local. PTR Ice Cube._ftp._tcp.local.

Inactive: SRV  en1     22 Ice Cube._ftp._tcp.local. SRV Ice-Cube.local.

Inactive: TXT  en1      1 Ice Cube._ftp._tcp.local. TXT 

Inactive: PTR  en1     26 _ssh._tcp.local. PTR Ice Cube._ssh._tcp.local.

Inactive: Addr en1      4 Ice-Cube.local. Addr 10.0.1.2

Cache currently contains 5 records; 1 referenced by active questions

11251: ServiceBrowse       _http._tcp.local.

10755: ServiceBrowse       _ftp._tcp.local.

10499: ServiceBrowse       _webdav._tcp.local.

10243: ServiceBrowse       _nfs._tcp.local.

 9731: ServiceBrowse       _afpovertcp._tcp.local.

 8195: ServiceRegistration Ice Cube._ssh._tcp.local.

 7939: ServiceRegistration Ice Cube._ftp._tcp.local.

mDNSResponder-58.4 (Jan 28 2004 16:31:36) ----  END STATE LOG  ----





[Feb 06, 2004]


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