Port exhaustion in Windows 7?

gavin2812 · 05 Feb 2014

Hi all,

I am having a problem with my Windows 7 Professional 64 bit install.

Occasionally, more so under heavy file transfer conditions, my PC has the following symptoms:

- DNS failure
- FTP server stops and displays '425 Can't open data connection.'

I don't think it's software specific as it seems to affect a number of applications running on the machine.

Rebooting the machine seems to fix the problems, but again, under heavy load (file transfers) it 'bombs out' and I have to reboot.

I have a fixed IP address to my DSL router (not using DHCP), not sure if this is relevant?

Not sure where to start with it really, I've run a few netstat commands but I cannot see that there are that many ports in use?

I'd appreciate any help on this and a pointer on where to start looking...

Thanks in advance

TanyaC · 05 Feb 2014

Hi,

it is unlikely that you will ever exhaust the ports available. There are 65536 of them. Ports below 1024 are reserved, as are some specific application ports. But there are 10's of thousands of ports available. Also, you can use multiple TCP and UDP connections per port.

This might be a router issue.

As a starting point, Have you tried rebooting the router? Or setting it back to factory defaults and reconfiguring it. It's also possible that you're overloading it.

For example, if you use torrents and you set your various configuration options to high values in attempts to maximize download speeds then you can reasonably expect your router to complain from time to time. Same can happen with http/ftp transfers.

Using a static IP address versus using a DHCP address should not make any difference.

If you have logs of the file transfers (cant tell you what/where because I don't know how you are doing the transfers), then posting relevant sections of that might help people to provide more assistance.

Tanya