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What Are the Common Causes of Socket Error 10051?

Alex Newth
Alex Newth

A socket error, such as socket error 10051, occurs whenever one computer attempts to connect to another network or server. Error 10051 happens because the other network is unreachable, usually because there is a problem with the router or modem on the computer attempting the connection. This can be as harmless as the router being shut off or a firewall getting in the way. At the serious end of the spectrum, the router may be misconfigured or may have been destroyed and is nonfunctioning.

Whenever a connection cannot be made, such as in the case of socket error 10051, one of the most common culprits is a firewall program. Though made to keep the computer safe, a firewall may restrict friendly connections. One should disable the firewall and see if the connection can go through. If the socket error still appears, then the firewall is not at fault.

Socket error 10051 is commonly caused by problems with a router or modem.
Socket error 10051 is commonly caused by problems with a router or modem.

If the router or modem is down, then there is no way for the computer to connect to another server. Someone may have bumped into the router or meant to reset the router and never turned it back on. Turning the router back on should restore the Internet server and allow the computer to connect to a server. If the router has been damaged, by being hit or having liquid spilled on it, for example, the router may need to be completely replaced.

A misconfigured router can cause socket error 10051. The misconfiguration means the router believes it cannot communicate with the server, so it doesn’t attempt the connection. Some advanced users may be able to find the problem, but it is best to call the Internet provider and get someone there to check out the router configuration. The provider will be able to find the problem and will tell the user how to fix it.

Some users have more than one router active at the same time. If there is more than one, one portion of the computer may believe it has to talk with one router, while another section believes another router has to be used. In this instance, neither router is designated as the primary router so neither will work. Configuring the computer to speak with only one router will alleviate this problem.

A similar problem that some users believe can cause socket error 10051 is when the computer is told not to use any router. This would cause the network to be unreachable, but it yields a different socket error. When the computer doesn’t have any router configured, this returns a socket error 10065.

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Discussion Comments


I had this problem with my SMTP server socket once. I couldn't send emails. It turned out that my email provider was blocking my access to the server. They removed the block and everything was fine after that.


@donasmrs-- If the server is not down, it could be an IP issue. The IP you're trying to connect to might be wrong. But if the server is down, you would most likely get a message like "no socket" error 10051 rather than the one you got.

It could also be the case that it has nothing to do with you. The other server might be temporarily down. You can retry at a later time.

Sometimes, after adding an exception to a firewall, it may be necessary to restart the computer for changes to take place. Newer computers don't have this issue but older ones might.


I keep getting socket error 10051 (the message says "connect error 10051"). My modem is working and I've checked the firewall and added an exception for the program. Nothing has changed, what could be the problem?

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    • Socket error 10051 is commonly caused by problems with a router or modem.
      By: vladimirs
      Socket error 10051 is commonly caused by problems with a router or modem.