Date: Tue, 09 Mar 2021 14:36:08 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 254159] Keepalive not working/tcp rst tolerance Message-ID: <bug-254159-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254159 Bug ID: 254159 Summary: Keepalive not working/tcp rst tolerance Product: Base System Version: 12.2-STABLE Hardware: amd64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: ant_mail@inbox.ru OS: 12.2-STABLE r368657 GENERIC amd64 I've ecnountered reproduceable problem with keepalive connection probes which tolerate TCP RST response. There is a connection between user application (client) and database (RDBMS) on FreeBSD server. After killing user application the connection is still alive (observed by netstat -x) on server. The keepalive timer for the connection (initially set to net.inet.tcp.keepidle value) is counting down. When it comes to zero, server send a keepalive probe. Client response with TCP RST packet. Then connection on server is still alive but keepalive timer resetted to net.inet.tcp.keepintvl value. After expiration of this interval server do not send any packet but reset keepalive timer of connection back to the net.inet.tcp.keepidle value. Then the things loop forever. P.S. There is no firewall. It is proofed that server recieves TCP RST from client (visible with tcp dump). RDBMS is running in jail. TCPdump from client: 193.017688000 192.168.0.3 192.168.0.2 TCP 66 3050→3583 [ACK] Seq=1 Ack=1 Win=1026 Len=0 193.017816000 192.168.0.2 192.168.0.3 TCP 54 3583→3050 [RST] Seq=1 Win=0 Len=0 1093.033029000 192.168.0.3 192.168.0.2 TCP 66 [TCP Dup ACK 5#1] 3050→3583 [ACK] Seq=1 Ack=1 1093.033154000 192.168.0.2 192.168.0.3 TCP 54 3583→3050 [RST] Seq=1 Win=0 Len=0 1993.113115000 192.168.0.3 192.168.0.2 TCP 66 [TCP Dup ACK 5#2] 3050→3583 [ACK] Seq=1 Ack=1 1993.113245000 192.168.0.2 192.168.0.3 TCP 54 3583→3050 [RST] Seq=1 Win=0 Len=0 ... -- You are receiving this mail because: You are the assignee for the bug.home | help
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