通过VPN使用RPostgres连接Redshift超时问题求助

I’ve run into similar VPN-related database connection headaches before, so here are practical, step-by-step checks to diagnose and fix your issue:

• Test basic network connectivity outside R first
  Skip R for a minute and use system tools to rule out core network blocks. Open your terminal and run either of these commands:

  telnet host.redshift.amazonaws.com 5439
  # If telnet isn't available, use netcat instead
  nc -zv host.redshift.amazonaws.com 5439
  

  If these commands also time out, the problem has nothing to do with R—it’s your VPN restricting traffic to Redshift’s host/port. Reach out to your IT team to confirm if Redshift’s domain and port 5439 are whitelisted for VPN users.

• Check if VPN is messing up DNS resolution
  VPNs often override your default DNS settings, which can lead to incorrect IP addresses for Redshift. Compare the resolved IP when you’re on vs. off VPN using these terminal commands:

  # Run while connected to VPN
  nslookup host.redshift.amazonaws.com
  # Run while disconnected from VPN
  nslookup host.redshift.amazonaws.com
  

  If the IPs don’t match, your VPN’s DNS is pointing you to the wrong address. As a temporary test, try using the working non-VPN IP directly in your dbConnect call (note: Redshift IPs can change, so this isn’t a permanent fix) or ask IT to adjust the VPN’s DNS configuration.

• Verify SSL compatibility with your VPN
  Your code uses sslmode = 'require', but some corporate VPNs block or interfere with SSL traffic. As an insecure temporary test (do NOT use this in production), try disabling SSL to see if it connects:

  con <- dbConnect(RPostgres::Postgres(), 
                   dbname = "db", 
                   host = "host.redshift.amazonaws.com", 
                   port = 5439, 
                   user = 'me', 
                   password = 'password', 
                   sslmode = 'disable')
  

  If this works, the issue is with the SSL handshake between your VPN and Redshift. Ask IT if they require a specific root certificate for SSL traffic, or if the VPN allows SSL connections to port 5439.

• Check if R needs proxy settings for VPN
  Many corporate VPNs force all traffic through a proxy server, and R doesn’t automatically pick up these settings. First, get your company’s proxy address and port from IT, then set these variables in R before connecting:

  Sys.setenv(https_proxy = "http://your-company-proxy:port")
  Sys.setenv(http_proxy = "http://your-company-proxy:port")
  

  Then retry your connection code.

• Confirm Redshift security group allows VPN IPs
  Even if you can connect off VPN, your VPN might assign you a new public IP that’s not allowed in Redshift’s security group rules. To find your VPN public IP, run this in your terminal:

  curl ifconfig.me
  

  Ask your DevOps team to verify if this IP (or the entire VPN IP range) is whitelisted in Redshift’s security group for inbound traffic on port 5439.

• Update RPostgres (last resort)
  While less likely, an outdated RPostgres version might have subtle compatibility issues with VPN network flows. Update the package and test again:

  install.packages("RPostgres")
  

内容的提问来源于stack exchange，提问作者Devin