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faq:tcpip [2018/02/17 19:55] – [SSH Kex Algo] updated to mention cryptlib 3.4.4 and issue with .ssh/config work-around if left in place digital manfaq:tcpip [2018/05/23 19:46] – [Bind] Added Linux errno example and netstat usage example digital man
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 |RLogin         |513 |- |Optional for quick-login from RLogin clients (e.g. SyncTERM)| |RLogin         |513 |- |Optional for quick-login from RLogin clients (e.g. SyncTERM)|
 |SMTP         |25 |- |Necessary for receiving Internet e-mail and inter-BBS instant messages| |SMTP         |25 |- |Necessary for receiving Internet e-mail and inter-BBS instant messages|
 +|Submission     |587 |- |Necessary for users to send Internet e-mail through the BBS from a standard e-mail client|
 |POP3         |110 |- |Allows BBS users to check their e-mail using standard Internet mail clients (e.g. Outlook Express)| |POP3         |110 |- |Allows BBS users to check their e-mail using standard Internet mail clients (e.g. Outlook Express)|
 |FTP         |21 |- |Allows access to the BBS file/download areas using a standard FTP client or web browser| |FTP         |21 |- |Allows access to the BBS file/download areas using a standard FTP client or web browser|
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   0420 !ERROR 48 binding FTP Server socket to port 21    0420 !ERROR 48 binding FTP Server socket to port 21 
  
-This usually means you have another TCP/IP server on your system that is already bound to (and is presumably already listening for incoming connections on) this port. This could be a pre-existing instance of Synchronet or any other Telnet/Web/Mail/FTP servers that you may have installed on your systemYou can use utilities such as [[man>netstat]] (for Windows or Unix) or [[http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx|TCPView]] (for Windows) to verify what programs (if any) have the TCP or UDP port in question already bound. If these utilities do not report any program is bound to (and listening) on this port, you can try Telnetting to the port in question and see if anything answers. If you're unable to connect to the port with a Telnet client and Synchronet cannot bind the port, your TCP/IP stack probably needs to be reset, so a system reboot may be in order+**Note:**\\ 
 +On Unix-like systems, the error number may be different, e.g''ERROR 98'' (EADDRINUSE) on Linux.
  
-If you're running a Unix-like operating system (not Windows) and get bind errors only when recycling servers, this is most likely because a TCP session is stuck in a ''TCP TIMEWAIT'' state (you can use netstat to verify this). The session will eventually time-out and close properly on its own, allowing the port to be re-bound at that time. To work-around this problem, you can either increase the ''BindRetryCount'' and/or ''BindRetryDelay'' values in your ''[[dir:ctrl]]/[[config:sbbs.ini]]'' file, or you can add the following line to your ''[[dir:ctrl]]/[[config:sockopts.ini]]'' file: +This usually means you have another TCP/IP server on your system that is already bound to (and is presumably already listening for incoming connections on) this port. This could be a pre-existing instance of Synchronet or any other Telnet/Web/Mail/FTP servers that you may have installed on your system. You can use utilities such as ''[[man>netstat]]'' (for Windows or Unix((e.g. 'netstat -naptu' as root user on Linux))) or [[http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx|TCPView]] (for Windows) to verify what programs (if any) have the TCP or UDP port in question already bound. If these utilities do not report any program is bound to (and listening) on this port, you can try Telnetting to the port in question and see if anything answers. If you're unable to connect to the port with a Telnet client and Synchronet cannot bind the port, your TCP/IP stack probably needs to be reset, so a system reboot may be in order.  
 + 
 +If you're running a Unix-like operating system (not Windows) and get bind errors only when recycling servers, this is most likely because a TCP session is stuck in a ''TCP TIMEWAIT'' state (you can use ''[[man>netstat]]'' to verify this). The session will eventually time-out and close properly on its own, allowing the port to be re-bound at that time. To work-around this problem, you can either increase the ''BindRetryCount'' and/or ''BindRetryDelay'' values in your ''[[dir:ctrl]]/[[config:sbbs.ini]]'' file, or you can add the following line to your ''[[dir:ctrl]]/[[config:sockopts.ini]]'' file: 
   REUSEADDR=1    REUSEADDR=1 
  
faq/tcpip.txt · Last modified: 2020/06/01 21:33 by digital man
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