Network weirdness


I am have a strange issue with connection to a server and I just dont understand it!

A client has a managed server at 1&1, no access to logs :frowning:

When connect to this server by FTP or SSH the connection will drop and then for a period I can not connect to the server by SSH, FTP or even HTTP yet I can ping the server and traceroute to it.

No one else has this issue and I have no problem with any other server.

From my end all I can find is that the server is rejecting my connection but according to 1&1 tech support there is nothing on the server that would black list an ipaddress.

I am using Suse 11.2 using Virgin Broadband, anyone else had this issue ?

Any ideas how I can find out what is going?

Sounds like it’s a fundamental networking issue, your session is interrupted only on one end and it sounds like the TCP/IP session has to timeout on the other end before you can establish another connection. It’s not a “blacklisting,” it sounds like a faulty network connection.

Depending on how regular the problem is, you may find it difficult to troubleshoot, if I were in your place I’d start by

  • Mapping the connection using route trace.
  • Comparing the above with other “problem free” connections to determine if the same routers are traversed, particularly if the gateway to the 1&1 network is different.
  • Consider if there’s anyone who might be trying to hack your connection (you may need to ask 1&1 to set up special logging to compare with your known connection attempts).
  • Is the Server restricted to number of connections? If so, maybe someone else is connecting and kicking you off.


Thanks Tony

your explanation makes sense which is a good start.

I have no problems with connection to any other servers though none are at 1&1.

I will approach the server administrator and see if I can convince them to investagte further.

Thanks again.