Environment
Novell NetWare 6.5
Novell Open Enterprise Server (NetWare based)
TCP/IP
TCPIP.NLM
PING
Three-way Handshake - SYN ACK
Novell Open Enterprise Server (NetWare based)
TCP/IP
TCPIP.NLM
PING
Three-way Handshake - SYN ACK
Situation
It is useful to check that TCPIP.NLM itself is working before trying to troubleshoot connection problems with NCP, CIFS, SMB, NFS, AFP or any other protocol that runs on top of it. For example:
- Unable to connect to server
- Server drops connections
- Client can PING server but not connect to it
- Performance problems
Resolution
The use of PING as a diagnostic is limited as it doesn't test if a connection can actually be made to the server, only that a server can respond.
To check if a three-way handshake is possible:
At the console: SET TCP UDP DIAGNOSTIC SERVICES = ON
At a workstation: telnet <Server IP> 19
This will set the server to listen on port 19 and generate lines of scrolling characters when Telnet successfully connects.
If baselining, diagnosing, debugging or troubleshooting performance issues, this can also be used to generate a steady, predictable stream of traffic that can be traced using a tool such as Wireshark or Ethereal.
To check if a three-way handshake is possible:
At the console: SET TCP UDP DIAGNOSTIC SERVICES = ON
At a workstation: telnet <Server IP> 19
This will set the server to listen on port 19 and generate lines of scrolling characters when Telnet successfully connects.
If baselining, diagnosing, debugging or troubleshooting performance issues, this can also be used to generate a steady, predictable stream of traffic that can be traced using a tool such as Wireshark or Ethereal.