forum.vdsworld.com

[jwfv]

I have a program that exchanges data with a web server. It does two things via the internet Extension Suite:

It uses an HTTP "Get" command to download a file to the local drive (for updates.)

It also uses the FTP function to send and receive files on a daily basis.

I have one user who is having firewall problems. They are locked down so tight that they can't even browse internet sites. The network admin will open a port for my program to go through, but which one should he open?

I'm assuming port 21, since it is the default FTP port.

For HTTP, would I use the Proxy function to route things through this port?

This is not my area of expertise, so any help is greatly appreciated.

[vdsalchemist]

Joe,
If the administrator is willing to open a port for you then all you should need is Port 21 for the FTP but I doubt that he/she would open that port. Unless there is an actuall proxy server using the proxy settings would not help much. If there is a proxy then yes by all means use the proxy for both HTTP and FTP but really you should be able to do just HTTP with a HTTP GET and to push the file use HTTP POST. I am not really into internet programming so I cannot give you specifics about the HTTP POST but there are others that are more into this area on the forum here.

[PGWARE]

A Proxy won't help if the box is locked down, the point is you won't be able to connect to the proxy either if ports are locked down.

If the admin will open a port he would be more likely to open port 80 (http) then 21 (ftp), since ftp provides a backdoor into the system once passwords have been sniffed. It's unlikely an admin who has locked down a system so tight like that would be willing to open up ftp.

I suggest asking to open up port 80 for http communication. You can then download files using http or get files this way.

OR

You can ask for a custom port and use standard TCP/IP to send/receive files. You will need to send data of a file as ascii characters and then re-assemble the file on the client/server end. Using BINFILE should allow you to get a file as a set of ascii characters which you can transmit using a tcp connection.

[jwfv]

Thanks for the info -

The internet extension DLL allows you to specify a port for FTP besides the default 21. Should I use this feature? Can I just pick a number, tell the network admin that number, and use that port - like port 25? And then just direct all my FTP stuff through port 25?

[Vic D'Elfant]

Just google at 'port <your port number>' to see if it's already taken by another process

Regards,
Vic

[tim6389]

or you can do a port scan with freeware s/w that is out there to one thing you said is port 25 if i recall port 25 is one of the ports for e-mail. if you have to uses ftp then i would uses like port 22

note: if you do a port scan with any s/w that is out there its best to let the admin know you are doing that. cuase so admin might get a little mad

other thing is can you have your porgram do all the fuction thru one port? if so that might be the best way this way the admin don't have to open more ports then what is needed.

I don't know if this info helps ya or not i hope it does

[tim6389]

here is a link that tells you what ports are used for. this way you can pick a port that other program is not using,etc

http://www.iana.org/assignments/port-numbers


hope this helps

[jwfv]

I'll do a little more checking of the way it is set up. Thanks for all the replies.