Network problem - wireshark logs

We have replaced a firewall with a Cisco ASA and we are experiencing odd errors in the network. Cisco don't believe it is the firewall itself (everything works fine with the old firewall though) and I have odd network trace logs that I can't resolve.

The attached screenshot is from an FTP connection which fails.

The first packet is sending a SYN packet to the FTP server, this is acknowledged, then the Dell 6248 switch which is doing routing for the VLAN's chips in with a redirect, etc.
However the second SYN ACK packet from the FTP server is replying on a totally different port. Why? I believe this is the problem but I cannot fathom where the problem lies.

This FTP server worked fine with the previous firewall and no other changes have been made to the network. However, is it possible that something was not configured correctly previously and is only now showing up?

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The Port You refer to is the source port and that i assigned by application and is in most of the time greater than 1023. Be sure you have opened the port 20 and 21 (ftp and ftp-data) to your destination on your ASA Firewall
partymarty84Author Commented:
It appears the NAT/Basic Firewall option under routing and remote access had been enabled on the FTP server. Problem resolved.

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How did it work before the change of the Firewall?
partymarty84Author Commented:
it was enabled while checking for another firewall issue related to VPN.
Ok Important is that it is resolved :)
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Network Analysis

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