Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

i've problems connecting to an ftp-server behind a cisco asa firewall using passive mode. ftp works using active and "extended passive" mode, however: when i turn off "extended passive" (epsv in ftp console client app), it does not work anylonger -- all commands result in a timeout. however we need non-"extended passive" mode for some application we use.

any ideas?

thanks, harald

UPDATE / SOLUTION

as it turns out, it was not exactly ASA's fault, or was it? i had to turn of masquerading in proftpd configuration. i had the masquerading-address in proftpd-config set to the IP address of the ftp-server domain and that resulted in unexpected things when passing traffic through the asa. now -- without address masquerading -- everything works very well.

share|improve this question

7 Answers 7

You need to enable application-level filtering for FTP using the "fixup" command:

# fixup protocol ftp 21

There is this article on the PIX that also applies to ASA:

http://www.ciscopress.com/articles/article.asp?p=24685

share|improve this answer
    
thanks for your fast reply. i tried, but it still does not work. i'm using proftpd behind the asa. i've looked at the ftp-logs and it seems, that proftp closes connection immediately when i switch to passive mode -- but the client says there was a timeout. –  harald Jun 29 '09 at 14:12

You may need to create a rule to allow the Pasv ports, not just port 21. In your FTP program usually they have a configuration setting where you can specify customer Pasv port range. Specify some high range of ports say 45200 to 45500 or something like that. Then in your ASA allow those ports to the IP of the FTP server.

share|improve this answer
    
hi, the port range is open, but no success :( –  harald Jun 29 '09 at 15:24

The ASAs don't have a fixup command like the PIX did.

Are you using the default inspections on FTP traffic via a service policy rule?

share|improve this answer
    
i've found some tutorial on another site, which told to use: class-map global-class match default-inspection-traffic policy-map global-policy class global-class inspect ftp but that did not work either, is it that what you ment? –  harald Jun 29 '09 at 14:26

Hi try the following things:

ftp mode passive

policy-map global_policy

class inspection_default

inspect ftp

I am not exactely sure what the first command does, but i saw it in a couple of running configs. just give it a try

but i am quite sure that you need to create a policy-map with an ftp inspection. that's the thing they called fixup protocols on the pix before. it allows the asa to open a session when the opposition choose on whitch port they want to talk.

share|improve this answer
    
yes, i've made this configuration -- but still no success –  harald Jun 29 '09 at 15:25
    
hmm i would suggest you do a packet capture to see if there are dropped packages. There is a easy way via ASDM. –  sam Jun 29 '09 at 16:55

You could switch to using implicit SFTP instead and then you only need to worry about a single port to open.

share|improve this answer

I think ftp passive mode is for the asa (router itself) to send, or recieve configs to or from itself. Not for passing sessions. Just what I've found....

share|improve this answer

I was talking about the command "ftp mode passive" just to clarify.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.