Question about Port Forwarding for FXP

ORDL · 02-23-2006, 12:07 PM

Hi,

I have recently started using FlashFXP from behind a hardware NAT router. At the same time, I now seem to be having trouble FXPing from site to site. Straight downloads work just fine.

Do I need to set my NAT router to forward additional ports? That's the only thing I can think of.

Thanks very much,
Mike Wang

* FlashFXP v[3].[20], build [1080], [X]registered, [ ]unregistered, [ ]pirated
* OS [X] WinXP, [ ] Win2K, [ ] Win98, [ ] WinME, [ ] Other
* Running behind NAT/router [X] Yes & Model [LinkSys RT31p2 ], [ ] No, [ ] Not sure
* Running firewall [ ] Yes, Name [ ], Ver. [ ], or [X] No
* Running Antivirus [X] Yes, Name [Norton 2006] or [ ] No
* Network [ ] xDSL, [X] CABLE, [ ] Dail-Up, [ ] Other

bigstar · 02-23-2006, 12:53 PM

NAT routers don't play well with site to site transfers.

There are a couple of ways around this problem, however they all require changes to the ftp server.
1. run the ftp server on a port other than 21. usually NAT only monitors port 21
2. connect to the site using ssl/tls, since the connection is encrypted NAT wont be able to do anything.

Basically what happens is that NAT is designed to prevent the ftp client from sending the wrong info to the ftp server. When the client sends the PORT command the NAT router modifies the packet to include the external IP of the router. This is fine for normal transfers but site to site transfers require the PORT command to be left as-is, since the IP address points to a ftp server.

ORDL · 02-23-2006, 04:42 PM

Thanks BigStar for taking the time to help me.

Both my source and destination FTPs are using SSL/TLS, so it should make no difference to NAT, if I understand you correctly. Yet other people are using FlashFXP to copy between sites, the only thing different I can see is that I use NAT and they don't.

Maybe I should try just bypassing my NAT router here and see if everything works with a direct connection. Then I'll know if it's the router or not.

MxxCon · 02-23-2006, 07:08 PM

yes, you should def try to fxp w/o your router to make sure that it is indeed cuasing those problems

zag2me · 02-24-2006, 03:14 AM

Also make sure you port 113 is open to allow ident

MxxCon · 02-24-2006, 08:01 AM

Quote:

Originally Posted by zag2me

Also make sure you port 113 is open to allow ident

well, doesn't look like ident is at fault here.
if it was a problem with ident, he wouldn't be able to connect to those sites in the 1st place...

ORDL · 02-27-2006, 04:57 PM

I have tried bypassing the NAT router over the weekend, and I am able to FXP fine when not going through NAT, so the think my router is the culprit.

I have tried forwarding ports 2030-2040 back to FXP at my router, and then setting this port range in the FlashFXP software (under Prefs/Connection/Limit Local Port Range To), but that hasn't helped me either. I thought ten open ports would be enough for FlashFXP to use. These changes have not hurt or helped anything, so obviously my reasoning in this is wrong.

Extremely grateful for any help, regards,
Mike

MxxCon · 02-27-2006, 07:12 PM

for FXP you really shouldn't have to open/forward ports(other than for LIST) since you aren't the one getting/transmitting data..
take a look at http://www.dslreports.com/forum/linksys they might have more experience with your specific router and might know how and what to change to solve your FXP issues.

but also make sure that you are indeed using SSL...i don't think your router is advanced enough to be able to snoop on encrypted connections, so if it's messing with your ftp, i suspect you might not be connecting using SSL or using SSL but w/o encryption.

ORDL · 03-03-2006, 04:56 PM

I followed your suggestion and contacted LinkSys Tech Support directly. Not much help there, they never even heard of "FXP", let alone any specific port information (they probably outsource their user support). So back to square one.