Configuring Ports for Efficient Usage of Sauce Connect Proxy – Sauce Labs

When many tests are run in parallel, Sauce Connect will become the aggregation point for lots of connections. This can easily exhaust the number of available TCP ports on the machine where Sauce Connect is running. If many tests will be run at once, we recommend that you increase the number of available ports, and make ports reusable on the machine running Sauce Connect. This article contains instructions on how to accomplish this on three platforms.

Without properly configuring the TCP ports on the machine that is running Sauce Connect, you might run into some of the these issues during test execution:

Slower and longer execution of tests
Possible timeout errors and failures in tests
Degraded performance in the Sauce Connect tunnel that can lead to the tunnel shutting down mid-execution
Degraded performance in the machine that is running Sauce Connect

Windows

Change these settings in the registry:

reg add 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters' /v MaxUserPort /t REG_DWORD /d 65534
reg add 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters' /v TcpTimedWaitDelay /t REG_DWORD /d 30

Check that the new values are in effect:

reg query 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters'

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
       ICSDomain    REG_SZ    mshome.net
       SyncDomainWithMembership    REG_DWORD    0x1
       DataBasePath    REG_EXPAND_SZ    %SystemRoot%\System32\drivers\etc
       NameServer    REG_SZ
       ForwardBroadcasts    REG_DWORD    0x0
       IPEnableRouter    REG_DWORD    0x0
       Domain    REG_SZ
       SearchList    REG_SZ
       UseDomainNameDevolution    REG_DWORD    0x1
       EnableICMPRedirect    REG_DWORD    0x1
       DeadGWDetectDefault    REG_DWORD    0x1
       DontAddDefaultGatewayDefault    REG_DWORD    0x0
       HostName    REG_SZ    WIN-HLEK05V71GA
       NV HostName    REG_SZ    WIN-HLEK05V71GA
       IPAutoconfigurationSubnet    REG_SZ    0.0.0.0
       IPAutoconfigurationMask    REG_SZ    0.0.0.0
       DhcpNameServer    REG_SZ    192.168.122.1
       TcpTimedWaitDelay    REG_DWORD    0x1e
       MaxUserPort    REG_DWORD    0xfffe

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Adapters
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\DNSRegisteredAdapters
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\NsiObjectSecurity
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\PersistentRoutes
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\TcpTimedWaitDelay
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Winsock

You need to reboot the machine for the new settings to take effect. See http://msdn.microsoft.com/en-us/library/aa560610(v=bts.20).aspx for more information about these settings.

Linux

To make ports in the TIME_WAIT state reusable, and thus avoid port exhaustion, enable these sysctls:

$ sudo sysctl -w net.ipv4.tcp_tw_reuse=1
   net.ipv4.tcp_tw_reuse = 1
$ sudo sysctl -w net.ipv4.tcp_tw_recycle=1
   net.ipv4.tcp_tw_recycle = 1

You can also reduce the time sockets spend in the TIME_WAIT state:

$ sudo sysctl -w net.ipv4.tcp_fin_timeout=1
net.ipv4.tcp_fin_timeout = 15

You don't need to reboot the machine for the changes to take effect.

You can make these settings permanent via:

$ echo "net.ipv4.tcp_tw_reuse=1"|sudo tee -a /etc/sysctl.conf
$ echo "net.ipv4.tcp_tw_recycle=1"|sudo tee -a /etc/sysctl.conf
$ echo "net.ipv4.tcp_fin_timeout=15"|sudo tee -a /etc/sysctl.conf

See http://vincent.bernat.im/en/blog/2014-tcp-time-wait-state-linux.html and http://kaivanov.blogspot.de/2010/09/linux-tcp-tuning.html for more information on what these settings do.

Mac OS X

To make more ports available to Sauce Connect, use this command:

$ sudo sysctl -w net.inet.ip.portrange.first=16384

To reduce maximum segment lifetime for TCP:

$ sudo sysctl -w net.inet.tcp.msl=15000

See http://rolande.wordpress.com/2010/12/30/performance-tuning-the-network-stack-on-mac-osx-10-6/ for more information on what these settings do.