OpenGGSN Fix for WAN TCP NAT binding timeouts
Budget: $30 – $250 USD
Help needed to work around a TCP NAT port binding timeout issue on the WAN network that our system uses. This is somewhat of a special case because the WAN is through satcoms.
Specifically, clients on the GGSN tun0 connection may keep TCP sessions open but silent for >5 minutes, and the satcoms closes unused TCP ports after silence for 5 minutes.
All we need is the GGSN to periodically generate a few additional TCP ACK messages for ports that have been silent for 2 minutes. We don't want to use the similar Linux global settings for tcp_keepalive_time because that impacts other TCP sockets.
I have a lab system available with source code on a public IP address you can access. I expect this will take about 10-15 lines of code and around 2-3 hours. More precise detail and explanation is in the attachment.
Ideal Skills & Experience:
- Proficiency in C programming and TCP sockets.
- Familiarity with Linux based systems
- Prior experience in debugging and fixing NAT issues.
The specific fix I have identified in the attachment would improve performance. Apply if you understand details in the attachment and have the above skills.
Specifically, clients on the GGSN tun0 connection may keep TCP sessions open but silent for >5 minutes, and the satcoms closes unused TCP ports after silence for 5 minutes.
All we need is the GGSN to periodically generate a few additional TCP ACK messages for ports that have been silent for 2 minutes. We don't want to use the similar Linux global settings for tcp_keepalive_time because that impacts other TCP sockets.
I have a lab system available with source code on a public IP address you can access. I expect this will take about 10-15 lines of code and around 2-3 hours. More precise detail and explanation is in the attachment.
Ideal Skills & Experience:
- Proficiency in C programming and TCP sockets.
- Familiarity with Linux based systems
- Prior experience in debugging and fixing NAT issues.
The specific fix I have identified in the attachment would improve performance. Apply if you understand details in the attachment and have the above skills.