On 31.03.2020 15:30, Mark Thomas wrote:
On 31/03/2020 13:29, André Warnier (tomcat/perl) wrote:
On 31.03.2020 14:20, Mark Thomas wrote:
On 31/03/2020 11:20, Aditya Kumar wrote:
Tomcat 9.0.30 on Windows Server 2012 / Java 1.8
I've noticed on a freshly installed version of tomcat 9, upon startup
there
are several connections to and from localhost on different ports
For example on my tomcat server there are 4 connections to and from
localhost (output from netstat)
TCP 0.0.0.0:8080 0.0.0.0:0
LISTENING 3972
TCP 127.0.0.1:55618 127.0.0.1:55619
ESTABLISHED 3972
TCP 127.0.0.1:55619 127.0.0.1:55618
ESTABLISHED 3972
TCP 127.0.0.1:55620 127.0.0.1:55621
ESTABLISHED 3972
TCP 127.0.0.1:55621 127.0.0.1:55620
ESTABLISHED 3972
TCP [::]:8080 [::]:0
LISTENING 3972
These can grow to a large number (several thousand) on a busy system.
What
are these connections used for? What caused them? What thread are they
attributed to?
The Java NIO implementation on Windows uses TCP for intra-process
signalling. It opens a pair of self-connected sockets for every Selector.
Mark
While we're at it, under Linux, are the following for a similar reason ?
output of : netstat -pan | grep 27514 (tomcat's JVM PID = 27514)
[...]
unix 2 [ ] STREAM CONNECTED 167427210 27514/java
unix 2 [ ] STREAM CONNECTED 167423436 27514/java
Don't know. One possible way to check would be to add an additional NIO
connector and see if you get more of them.
Note : this is not very important, was just curiosity
But Nope.
I added a second HTTP Connector (port 8180), which by default should be NIO :
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
<!-- just for a test -->
<Connector port="8180" protocol="HTTP/1.1"
address="127.0.0.1"
connectionTimeout="20000"
redirectPort="8443" />
and restarted tomcat, but the number of listed unix sockets remains the same :
root@xxx:~# netstat -pan | grep 32647 (tomcat 8.5 has a new PID)
tcp6 0 0 127.0.0.1:8005 :::* LISTEN
32647/java
tcp6 0 0 127.0.0.1:8009 :::* LISTEN
32647/java
tcp6 0 0 :::8080 :::* LISTEN
32647/java
tcp6 0 0 127.0.0.1:8180 :::* LISTEN
32647/java
tcp6 0 0 127.0.0.1:8009 127.0.0.1:45190 ESTABLISHED
32647/java
unix 2 [ ] STREAM CONNECTED 190838270 32647/java
unix 2 [ ] STREAM CONNECTED 190846897 32647/java
root@darwin:~#
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
For additional commands, e-mail: users-h...@tomcat.apache.org
