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. Mark --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
