topic Re: FTP over TLS not working in Network Security

FTP over TLS not working

piatthi1983 — Mon, 11 Mar 2019 23:14:24 GMT

hi all,

i configured port redirection on ASA to allow external user access to Internal FTPS Server. but it's not working

i use Filezilla client to access but i have this error.

Statut : Connexion à x.x.x.x:21...

Statut : Connexion établie, attente du message d'accueil...

Réponse : 220-Microsoft FTP Service

Réponse : 220 FTP-Server FTP

Commande : AUTH TLS

Réponse : 234 AUTH command ok. Expecting TLS Negotiation.

Statut : Initialisation de TLS...

Erreur : Délai d'attente expiré

Erreur : Impossible d'établir une connexion au serveur

please can somebody know what can cause this issue ?

thanks for your help

FTP over TLS not working

Julio Carvajal — Fri, 01 Jun 2012 15:49:08 GMT

Hello,

Is this FTPS server working on active mode?

Can you share the nat configuration for the server?

Regards,

Julio

FTP over TLS not working

piatthi1983 — Fri, 01 Jun 2012 15:55:16 GMT

ASA is configured in Passive Mode.

this is NAT configuration

static (DMZ1,outside) tcp interface 20 'ftps-server-private IP' 20

static (DMZ1,outside) tcp interface 21 'ftps-server-private IP' 21

access-list outside_access_in extended permit tcp any host 'Outside_public_IP' eq 20

access-list outside_access_in extended permit tcp any host 'Outside_public_IP' eq 21

FTP over TLS not working

Julio Carvajal — Fri, 01 Jun 2012 16:32:46 GMT

Hello,

Here is a document that you will need to read

https://supportforums.cisco.com/docs/DOC-23206

As you can see you will be using FTPS (FTP over SSL) that uses port 990 for the control channel (this information is encrypted) and the data channel goes on plain text.

Is there a way you can use a static one to one and then allow port 990 on the outside ACL?

Regards,

Re: FTP over TLS not working

hobbe — Fri, 01 Jun 2012 19:02:00 GMT

FTPS is not supported in the ASA.

Due to the problem of traffic beeing encrypted.

However you can in some FTPS servers setup that you are only able to use some few ports.

Then you can open for all those ports that you have choosen.

If you want a better alternative than FTPS use SFTP.

FTPS is firewall unfriendly

SFTP is firewall friendly

SFTP will work correctly all the time.

Good luck

HTH