B Wyatt created TS-1424:
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Summary: Transparent proxy with
proxy.config.http.use_client_source_port==1 has problems if the client is
keep-alive and the origin server is not.
Key: TS-1424
URL: https://issues.apache.org/jira/browse/TS-1424
Project: Traffic Server
Issue Type: Bug
Environment: 3.2 with transparent (TProxy) interception +
proxy.config.http.use_client_source_port = 1
Reporter: B Wyatt
Assignee: Alan M. Carroll
As keep-alive is hop-to-hop ATS will happily support client keep-alive in
instances where an Origin Server terminates the connection after each
transaction.
However, when using proxy.config.http.use_client_source_port this behavior can
cause some sites to break.
When the client is kept alive, subsequent requests are made rapidly and with
the same 4-tuple for addressing. Since ATS is trying to match the 4-tuple (due
to proxy.config.http.use_client_source_port) it enters a 3-way race between:
# the FIN, FIN/ACK packets being exchanged with the origin server and the new
request packets from the client. If the OS is slow it is possible that ATS
will attempt to reconnect with the same port/address before the connection is
legitimately closed.
# Kernel timers for PAWS and recently closed sockets. This is different (and
much shorter) than the time-wait state and there is no way to disable it
# Everything working out just fine and the connection establishing like normal
The best repro case I've seen is a slow origin server that serves pages in
<frame> tags from the same host but does not support keep-alive
(http://publib.boulder.ibm.com/infocenter/lnxinfo/v3r0m0/index.jsp for instance)
It is possible that simply respecting a servers keep-alive settings when using
proxy.config.http.use_client_source_port would work as the original client
would change the 4-tuple address for its next connection.
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