SSID
John Stubbings
permissible in a SSID ESSID
like leading spaces what symbols etc
TIA
curly Bill
From whom are you getting permission?
I didn't know there were rules in such matters.
Jeff Liebermann
It should be in the IEEE 802.11 specification.
<http://standards.ieee.org/getieee802/802.11.html>
From IEEE 802.11-1999 7.3.2.1
7.3.2.1 Service Set Identity (SSID) element
The SSID element indicates the identity of an ESS or IBSS.
See Figure 35.
The length of the SSID information field is between 0 and 32 octets.
A 0 length information field indicates the broadcast SSID.
That's a bit misleading as the SSID is sometimes null terminated
leaving only 31 characters available. Some firmware versions screw up
if you use the full 32 characters.
The characters must also be printable, so no control characters are
allowed. I'm fairly sure that a leading space is also not allowed,
but there doesn't seem to be anything specified.
Also: The following six characters are not allowed: ?, ", $, [, \, ],
and +. In addition, the following three characters cannot be the first
character: !, #, and ;.
From a previous posting:
>Can i use spaces like "my home accesspoint" or must it be without speces
>"myhomeaccesspoint"
Spaces are just fine. Some utilities will blow up if you do that, but
most access points handle it just fine.
>Are there any other rules for SSID´s?
Maximum humor, keep it clean, forget about bell characters, and no
nulls.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 je...@comix.santa-cruz.ca.us
# http://802.11junk.com je...@cruzio.com
# http://www.LearnByDestroying.com AE6KS
Jeff Liebermann
>John Stubbings wrote:
>> Can anyone point me to a reference [rfc] that says what exactly is
>> permissible in a SSID ESSID
>>
>> like leading spaces what symbols etc
>>
>> TIA
> From whom are you getting permission?
Give? I *SELL* permission. Pay me.
>I didn't know there were rules in such matters.
Specification writing is the art of micromanagement. There is a rule
for everything. If not, one will be produced. Sometimes, there are
even more than one rule for everything. Without rules, there would be
nothing for me to break.
John Stubbings
news:odjhl3p0238br63dn...@4ax.com...
> On Thu, 6 Dec 2007 21:40:24 -0000, "John Stubbings"
> <anna.riceD...@virgin.net> wrote:
>
>>Can anyone point me to a reference [rfc] that says what exactly is
>>permissible in a SSID ESSID
>>
>>like leading spaces what symbols etc
>
> It should be in the IEEE 802.11 specification.
> <http://standards.ieee.org/getieee802/802.11.html>
>
> From IEEE 802.11-1999 7.3.2.1
> 7.3.2.1 Service Set Identity (SSID) element
>
> The SSID element indicates the identity of an ESS or IBSS.
> See Figure 35.
>
> The length of the SSID information field is between 0 and 32 octets.
> A 0 length information field indicates the broadcast SSID.
>
> That's a bit misleading as the SSID is sometimes null terminated
> leaving only 31 characters available. Some firmware versions screw up
> if you use the full 32 characters.
>
> The characters must also be printable, so no control characters are
> allowed. I'm fairly sure that a leading space is also not allowed,
> but there doesn't seem to be anything specified.
Tested with my Cisco access point with latest firmware
Does not allow trailing spaces
Does allow leading spaces, tested and it works with XP and FreeBSD system
>
> Also: The following six characters are not allowed: ?, ", $, [, \, ],
> and +. In addition, the following three characters cannot be the first
> character: !, #, and ;.
Again tested with Cisco they say only + ] / " TAB and trailing space is
invalid
Tried ? and it works
Tried leading ! and it works
LR
and transfer data rather than just see the SSID.
From the Cisco info. I have seen they are quite clear that those
characters are not to be used.
<http://www.exio.com/univercd/cc/td/doc/product/wireless/airo1130/1130hig/113h_c3.htm>
Plan9
Interesting. It appears that in the absence of "specific and detailed"
valid SSID characters vendors have made up their own restrictions. I
looked at "ANSI/IEEE Std 802.11, 1999 Edition (R2003)" and could not find
any restrictions to the characters it might contain, only that it is an
octet string of size 0-32. I admit my look was very cursive and I may have
missed something, but it appears IEEE have dealt extensively with size and
use of SSID and almost nothing on what it can contain.
In my own case I have two Linksys wireless routers (WTR54G and BEFW11S4)
with SSIDs of the type #naaaaaa (e.g. #5window) and they both work with XP
and Kubuntu.
Question:
If the standards do not specify restrictions and a vendor applies
restrictions, is that a violation of the standards?
--
Ben
Jeff Liebermann
There are bigger holes in the 802.11 specs than a failure to specify a
char or string field type. Nobody ever considered the possibility
that users would want to intentionally obscure the SSID, hide the
SSID, or use it as any form of security. The previous standard was
published in 1997 and I vaguely recall (and am too lazy to research)
was originally inscribed in about 1994/1995. Now, think about where
we were in computing 12 years ago and see if you could predict current
applications. I think Windoze 3.1 and Xenix was the fashion. Linux
hadn't even been started. Next, try to predict where we'll be 12
years in the future and write an airtight spec that includes all
possible creative interpretations and mutiliations. Be sure to make
it compatible with systems that do not yet exist, with future security
considerations, with future government regulations, and with predicted
fashion trends. If you can do that, I wanna buy the crystal ball
you're using.
>In my own case I have two Linksys wireless routers (WTR54G and BEFW11S4)
>with SSIDs of the type #naaaaaa (e.g. #5window) and they both work with XP
>and Kubuntu.
>
>Question:
>If the standards do not specify restrictions and a vendor applies
>restrictions, is that a violation of the standards?
I lifted the SSID restrictions from the Cisco SSID Manager release
notes. See 2nd paragraph:
<http://www.cisco.com/warp/public/779/smbiz/prodconfig/help/eag/122-15.JA/1400br/h_ap_sec_ap-client-security.htm>
My guess(tm) is that the various strictures are the result of various
Cisco programs and shell scripts blowing up if confronted with these
characters. That would certainly explain the strictures on the
leading ! # ; which would probably blow up a Bourne Shell or Perl
script. Leading and trailing spaces will cause problems with HTML in
the configuration utilities. I found the problem with the null string
delimiter which resulted in a 31 character SSID, instead of 32. As
long as the management and configuration program handles the SSID as a
string, there's going to be scripting problems.
As for violating 802.11 standards, methinks you should take that up
with the Wi-Fi Alliance, which offers various certifications:
<http://www.wi-fi.org/wp/wifi-alliance-certification/>
<http://www.wi-fi.org/certification_programs.php>
However, I don't think you're going to get their attention. They have
successfully ignored the ASCII versus Hex WEP key concompatibility
between different vendor implimentations for years. There are also
some rather creative timing incompatibilities, such as those between
Meru Networks and Cisco. The Wi-Fi Alliance apparently (my guess) has
no interest in becoming an enforcement organization and is only
interested in selling certifications.
Incidentally, I recently had a customer discover that it was possible
to create a UserName in Vista that starts with a space. It was a typo
error but it's driving me nuts because some utilities accept the
leading space, while others do not. Directory names that start with a
space are officially proscribed, but I'm still stuck with:
c:\home\ user\
I can rename the user, but this customer already created a 2nd user
with the same UserName, but without the leading space. Now, he's got
files scattered all over the machine and randomly destributed between
the two UserNames depending on how various utilities and programs
handle the leading space. Worse, I can't move everything to a 3rd
neutral UserName because he has multiple network authentication
accounts all configured with the UserName.
So, go ahead. Try using a leading space and see what breaks.
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Jeff Liebermann
>The previous standard was
>published in 1997 and I vaguely recall (and am too lazy to research)
>was originally inscribed in about 1994/1995. Now, think about where
>we were in computing 12 years ago and see if you could predict current
>applications. I think Windoze 3.1 and Xenix was the fashion. Linux
>hadn't even been started.
Oops. So much for my photographic memory.
Linux was announced in 1991:
<http://www.linux.org/people/linus_post.html>
In 1995, SCO announce the end of Xenix support. OpenServer 5 had just
been released. At least I got the Windoze 3.1 right.
<http://www.computerhope.com/history/>
Grumble...
John Stubbings
news:EKCdnUAbE62DpcTa...@bt.com...
What I quoted was from a pop up box generated by Cisco software on 1100
access point when I put a trailing space in the SSID
System Software Filename: c1100-k9w7-tar.123-8.JEC
System Software Version: 12.3(8)JEC
Just tried SSID of ?$[\ no leading or trailing spaces, and it
worked :) and yes transferred data. Cisco access point FreeBSD client.
Anyway enough silliness I guess there is no definitive answer.
John Stubbings
news:rbril39u1u6iihn3g...@4ax.com...
Interestingly the problem I was trying to solve was exactly that. A client
trying to logon to an access point and the software trimmed the leading
space.
Not my access point I hasten to add. It wouldn't even occur to me to put in
a leading space.
Anyway problem solved. Next.
Aaron Leonard
~ permissible in a SSID ESSID
~
~ like leading spaces what symbols etc
~
~ TIA
Per the IEEE 802.11 standards, which are the standards that count,
if you're looking for standards, there are no restrictions on the
value of the octets in the SSID string. I.e. any value from 0 through
255 may be used in any octet.
That said, specific implementations may have issues with particular
octet values, for various reasons. For example, as some have noted,
Cisco products will sometimes assert that they forbid certain characters.
This is not because the use of those characters violates a *standard*,
but because those characters cause problems for things like the IOS CLI
parser and the HTML parser etc. Clients may exhibit similar limitations.
From an interoperability standpoint, you're better off sticking to
straightforward characters in your SSIDs. It's not as though using
exotic octet values in your SSID is going to confer any real
security benefit.
Aaron