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ASA 5515-X: Users cannot access FTP servers outside our network

Posted on 2014-03-14
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Last Modified: 2015-10-09
I've got a bit of a strange issue in one of our client networks.  We recently set up a brand new network for them using a new ASA 5515-X as the main firewall.  Things work great (these new devices are very powerful!) but despite my best efforts client computers are unable to access FTP servers outside of our network.

One additional complication is that we have an FTP server inside our network that is externally accessible, so port 21 is NAT'd for that system.  However I disabled that rule as a test and nothing changed.

Attached is a sanitized config for our firewall
Sanitized-Config.txt
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Question by:ravib123
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by:omarfarid
ID: 39930130
FTP works on two TCP ports 20 & 21

make sure firewall allows these ports
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by:Dave Baldwin
ID: 39930136
This question gets asked fairly often.  FTP requires ports 20, 21, and a range of ephemeral ports above port 1024.  That makes it a pain to set up in a firewall.  There are probably specialized config instructions somewhere to tell you how to do that in the ASA 5515-X.
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by:Mohammed Khawaja
ID: 39930314
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by:ravib123
ID: 39943898
You need add the following lines to your configuration:

policy-map global_policy
 class inspection_default
  inspect ftp

Already tried that - check the configuration posted.  No effect.
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by:ravib123
ID: 39943908
FTP works on two TCP ports 20 & 21

make sure firewall allows these ports

Yes it does.  The firewall is configured to allow both of these ports from anything to anything.
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by:ravib123
ID: 39943919
This question gets asked fairly often.  FTP requires ports 20, 21, and a range of ephemeral ports above port 1024.  That makes it a pain to set up in a firewall.  There are probably specialized config instructions somewhere to tell you how to do that in the ASA 5515-X.

This is true for Passive FTP connections - however that would suggest that I can only have a single client PC on the entire network functional, and I simply cannot forward these ports to a single client PC when I already have them forwarded to our FTP server for salespeople and customers to access.
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Dave Baldwin earned 500 total points
ID: 39943953
No, that is true for both active and passive connections.  The only difference is whether the client or the server chooses the 'ephemeral' ports.
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