CODEWITHSUNDEEP
network-programmingtelnet
Greg Charles
Greg Charles

Reputation: 2000

telnet to a port fails: fuzzy on basic network theory

When some network connection isn't working right, one thing in my bag of tricks is to try opening a telnet connection to it. I don't expect to be able to do anything useful with this connection, but knowing if I can or can't connect is helpful in diagnosing the problem.

So today we had a problem where our app server couldn't open the JDBC connection to our database. However, it works fine when the app server is on the same physical box as the database. Aha, I thought, there must be a firewall blocking that port. So I tried to telnet to that port, and couldn't connect. As a control though, I also telnetted to a database on a box we could connect to and that failed as well. So, the situation is, somehow whatever is listening on that port accepts a JDBC connection from JBoss, but rejects a connect from telnet. How does it distinguish these two connections? Different protocol? Password embedded in the connection request?

Upvotes: 0

Views: 565

Answers (1)

dMb
dMb

Reputation: 9367

Sounds like the database is only accepting connections on the local interface. Is your app server configured to connect to the database via its IP or via either localhost or 127.0.0.1?

Upvotes: 0

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