We have an 2003 IIS that if we browse via the local IP address works perfectly for both web site and FTP purposes however when we try to acess this via the public ip address we can't connect to it. We have forwarded ports 80 & 21 to the IIS and checked this umpteen times. There is no local firewall on the server. If we telnet on to port 21 the screen goes blank for about 10 seconds then returns to the c:> prompt. If we telnet on port 80 we get "could not open connection to host on port 80: connection failed"
We know that port forwarding works on the router as we have other open ports that work fine. We'd be most grateful for any ideas... many thanks
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Thanks feptias.. yes we had already looked at that one and it is definately on the right router.. One thing we have since found out is that no matter what we port forward to this server it won't work r.g. rdp, radmin, vnc, http, ftp etc. We've also tried the server on 4 different ip addresses. It's as if the server is rejecting and port forwarded connections.....??? I feel we are missing something glaringly obvious
A sensible next step would be to run wireshark on the 2003 server. It's a packet tracer. That way, you can see if the forwarded packets are reaching your server.
Are you sure your test method is valid. For example, testing port forwarding configured on the WAN port of a router is not normally possible from a PC that is already behind the same router (on your LAN). You must test using a PC that is on the Internet.
Not seen wireshark before but seems simple enough.. When running we tried to telnet all the forwarded ports to this server but nothing was picked up.
Yes all testing has been done to the server with workstations that are outside the lan. If we create a vpn everything works... but obvioisly that is not what we want... Thanks again
Is it possible that you need to modify firewall rules (or NAT rules) as well as setting port forwarding? Usually the two are configured with a single setting, but it might vary from one make of firewall to another. It sounds suspicious that you can reach the server using VPN, but not using port forwarding.
To give you an example, the SonicWall Pro series of firewalls (with which I am familiar) have separate places where you configure NAT rules and firewall rules. You have to get both right for it to work, especially if you have more than one static IP address assigned to the WAN port of your firewall/router. If you have multiple static IP addresses on the same firewall/router, then you need to make sure the same IP address is being used as the apparent sender of any outbound IP packets as is used to receive the inbound IP packets that you are forwarding to the server. You can check what IP address your server appears to be on by going to whatsmyip.com using a browser on the server.
I use a Draytek router/firewall at home. If your Draytek is anything like mine, then the rules for setting up port forwarding are, at best, obscure. On mine, it requires settings in one or more of the following:
NAT>Port Redirection
NAT>Open Ports
Firewall>General Setup
Firewall>Filter Setup
...and even then the filter setup is weird and obscure. I hope your Draytek is a little easier!
Feptias... We have a lot of experience with the Draytek range and find them relatively simple to configure.
To re-cap port forwarding works on 80 & 21 and any other port we care to forward to any other server bar the IIS. Yet all that we want to do with the IIS (web hosting, RDP, FTP etc.) works perfectly from behind the firewall via its local IP address. Its as if the IIS is rejecting any port forwarded IP addresses from the router.
Tornado V... a good idea but not the case because i can port forward ports 80 & 21 to an SBS and access it externally without any problem
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by: feptiasPosted on 2008-05-08 at 04:49:41ID: 21523864
Check the default gateway setting on the 2003 server. If it is sending return packets through a different router to the one that it received them from then connections from the Internet will fail.