To ftp or to sftp

Article by Rampant author Laurent Schneider

Ftp is seen as an old-time unsecure protocol. Many shops nowadays have switched or are switching to sftp. I will try to point out some differences: 

Compatibility: none. The protocol is completely different. Multiple graphical clients however do support both mode. But the basic “ftp” client will not work with sftp. 

Ascii mode: only in ftp. In sftp, it is always binary so there will be no conversion. Also no blocksize, recordlength or primary/secondary space for your OS/390 connections. 

Interactive mode: similar. you enter your username and password, do cd, put and get. But to quit, by will not work in sftp Use quit or exit instead. 

Batch mode: different. Most probably you will end up setting a private/public key infrastructure for your ssh connection and use scp (secure copy). If you are using a ssh client like putty, it is possible to do something like pscp -l user -pw password server:file .  

Security: sftp is secure, ftp is not. 

Speed: ftp is fast, sftp is slow! 

Oh NOOOOOOO!!!!! What’s the point is bringing something new if it is slower!!! 

Ok, let’s try to download a 100m file: 

$ time (echo "open dbsrv01
user oracle secret
bin
get 100m"|ftp -n ) 

real    0m24.673s
user    0m0.030s
sys     0m0.016s
$ time scp -q oracle@dbsrv01:100m . 

real    1m46.978s
user    0m0.108s
sys     0m0.202s

it is about 4x slower! Is there anything we could do about it?

Well, maybe :

$ time scp -q -o Compression=yes oracle@dbsrv01:100m .

real    0m18.634s
user    0m0.748s
sys     0m0.452s

ssh/scp/sftp have a compression mode. If you are transferring your large files across a slow network, this may be an interesting option to consider!