Archive for March, 2013

Repurposing netbook into gateway, firewall, AP

March 20th, 2013 No comments

The older netbooks, such as ASUS EEE 900 series, have gone down in price. I bought a refurbed EEEPC 900A w/1GB RAM, 4GB SSD and turned it into my gateway, firewall and local AP.  Upgraded memory to 2GB RAM, and added an external 8GB SD flash.

I loaded Fedora Core 17 Security Distro on it.  Now I have a nice, cheap gateway, firewall and AP (although only 802.11G speed).

I’ll add more to this as I have time…..

Unfortunately the netbook only have one wired 100M enet.  I need at least GigE interfaces.  I am currently looking at the

OEM Production 2550L2D-MxPC

which is an Atom D2550 based system with 2 Broadcom GigE, small, lower power and up to 8GB of RAM.  This should last me a long time as a router/gw/fw.

More to come….


File transfer speed over ssh

March 5th, 2013 5 comments

I’ve known that ssh encryption has an effect on the speed of file xfers. So doing thing such as rsync (which will use ssh) or even plain scp can be pretty darn slow, especially on large files and on system with old/slow CPU.

I also know about the recommendation to use different type of encryption when transferring files. Some people recommend blowfish, others arcfour. So I thought I’d do a little bit of testing in a controlled environment.

I have two recent vintage HP servers with the following specs.

HP ProLiant DL360p Gen8
Dual quad core Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz (8 core, 16 threads total)
4 x 3TB, mdadm RAID10, formatted as XFS, mounted noatime,logbufs=8
Tigon ethernet NIC, connected as GigE, full duplex to HP ProCurve 2848 switch
(both servers connected to same switch)

The test file is:
3921247501 Mar 4 08:22 bigdata.tar.bz2 (3.8GB)

I am using OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010
Kernel is 3.8.1-1.el6.elrepo.x86_64 #1 SMP Thu Feb 28 19:15:22 EST 2013 x86_64 x86_64 x86_64 GNU/Linux

I am going to copy this file from hp1 to hp2, using scp, rsync and ftp. With scp, I’ll try different encryption, no compression to see how the different encryption affect the transfers. For comparison purposes, I also timed using plain ole FTP transfer, which mean no encryption and very little system processing; and the timing proves that.  Also tested with plain rsync protocol (direct to rsyncd).

I run this 3 times. Without specifying encryption, ssh/scp will use the default, which depends on the version of OpenSSH (for this version, the default is aes128-ctr).  NOTE: the file is rm’ed each time at the dest before I do copy.

run Xfer type real user system
1 scp -o Compression=no 0m52.175s 0m12.709s 0m6.504s
2 scp -o Compression=no 0m47.872s 0m12.603s 0m6.806s
3 scp -o Compression=no 0m49.317s 0m12.748s 0m6.710s
1 scp -c arcfour -o Compression=no 0m49.536s 0m14.161s 0m6.903s
2 scp -c arcfour -o Compression=no 0m49.088s 0m14.045s 0m6.921s
3 scp -c arcfour -o Compression=no 0m50.698s 0m14.162s 0m6.728s
1 scp -c blowfish-cbc -o Compression=no 0m58.673s 0m44.295s 0m13.495s
2 scp -c blowfish-cbc -o Compression=no 0m56.399s 0m43.860s 0m9.036s
3 scp -c blowfish-cbc -o Compression=no 0m54.869s 0m43.949s 0m10.673s
1 scp -c aes128-cbc -o Compression=no 0m49.776s 0m14.641s 0m7.083s
2 scp -c aes128-cbc -o Compression=no 0m48.527s 0m15.154s 0m7.068s
3 scp -c aes128-cbc -o Compression=no 0m50.554s 0m15.334s 0m6.983s
1 ncftpput -m -u ftptest -p ‘XXXXXX’ hp2 /data/ /data/bigdata.tar.bz2 0m34.306s 0m0.141s 0m4.062s
2 ncftpput -m -u ftptest -p ‘XXXXXX’ hp2 /data/ /data/bigdata.tar.bz2 0m33.351s 0m0.160s 0m3.863s
3 ncftpput -m -u ftptest -p ‘XXXXXX’ hp2 /data/ /data/bigdata.tar.bz2 0m33.839s 0m0.154s 0m3.732s
1 rsync –stats -a /data/bigdata.tar.bz2 hp2::data/bigdata.tar.bz2.1 0m33.485s 0m10.221s 0m6.692s
2 rsync –stats -a /data/bigdata.tar.bz2 hp2::data/bigdata.tar.bz2.2 0m33.490s 0m10.234s 0m6.703s
3 rsync –stats -a /data/bigdata.tar.bz2 hp2::data/bigdata.tar.bz2.3 0m33.497s 0m10.163s 0m6.545s

In terms of speed, we have:

Average over 3 runs

RSYNC:         real=33.491  user=10.206  sys=6.6467
FTP:           real=33.832  user=0.1517  sys=3.8857
AES128-CBC:    real=49.619  user=15.043  sys=7.0447
ARCFOUR:       real=49.774  user=14.1226 sys=6.8507
AES128-CTR:    real=49.788  user=12.687  sys=6.6734
BLOWFISH-CBC:  real=56.647  user=44.0347 sys=11.068

So it look like in modern OpenSSH, using AES, it’s a wash which cipher/encryption method you want to use.

Note that rsync protocol itself is pretty darn efficient, slightly faster than FTP.

3/6/13 Update

AES in SSH.  I’ve tested again from an old Dell using Pentium 4 to the fast HP, with no AES support in hardware and the default AES128-CTR is much slower.  However, good news is that AES128-CBC is still faster than BLOWFISH, but slightly slower than ARCFOUR.  As for FTP and RSYNC, they are neck-and-neck in speed, no clear winner.

So my conclusion is that whether using AES with hardware support (in new Intel CPUs) or software, using the CBC (block mode) variant of AES is usually good enough.