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AirPcap NX adaptors can be configured to capture data on 40MHz channels but you will need to determine the “extension channel”

What is an Extension channel?
For 802.11n adapters, use of the Extension Channel enables a “wide” channel to be used. The choices for setting the extension are -1 (the preceding 20MHz frequency band), 0 (no extension channel), or +1 (the succeeding 20MHz frequency band). (The channel of the additional frequency band is called the extension channel).

The AirPcap adaptor configuration Extension Channel list box lets you choose a valid extension channel (above or below) for a given channe (see figure 1 below).

Not all channels have above and below extension channels:

For example, BG channels 1, 2, 3, and 4 do not have a -1 (below) extension channel. The reason is that the center frequencies of the primay and extension channels need to be separated by 20MHz. So if 4 were the primary channel, channel 1 (which is the lowest BG center frequency) is only 15 MHz below channel 4.

Figure 1

Outbound Caller ID: [your sipgate userid]

PEER Details:
————
type=friend
insecure=invite
nat=yes
username=[your sipgate userid]
fromuser=[your sipgate userid]
fromdomain=sipgate.co.uk
secret=[your sipgate password]
host=sipgate.co.uk
qualify=yes
canreinvite=no
dtmfmode=rfc2833
context=from-sipgate
disallow=all
allow=ulaw&alaw

USER Context: [your sipgate userid]

USER Details:
————-
authuser=[your sipgate userid]
context=from-trunk
nat=yes
dtmfmode=info
fromdomain=sipgate.co.uk
fromuser=[your sipgate userid]
host=sipgate.co.uk
insecure=very
secret=[your sipgate password]
type=peer
username=[your sipgate userid]
disallow=all
allow=ulaw&alaw

Register String: [your sipgate userid]:[your sipgate userid]@sipgate.co.uk/[your sipgate userid]

NOW CONFIGURE INBOUND ROUTE:
—————————-

DID Number: [your sipgate userid]
Then route to target (e.g. an extension) of your choice.

1. Ivan Pepelnjak – Introduction to Virtual Routing and Forwarding (VRF) tables
2. Keith Barker – Cisco VRF and troubleshooting

UNIX SECURITY TECHNICAL IMPLEMENTATION GUIDE
Version 5, Release 1

Can be downloaded from: http://iase.disa.mil/stigs/downloads/pdf/unix-stig-v5r1.pdf

In fact, the term X.509 certificate usually refers to the IETF’s PKIX Certificate and CRL Profile of the X.509 v3 certificate standard, as specified in RFC 5280, commonly referred to as PKIX for Public Key Infrastructure (X.509).

X509 File Extensions

The first thing we have to understand is what each type of file extension is.   There is a lot of confusion about what DER, PEM, CRT, and CER are and many have incorrectly said that they are all interchangeable.  While in certain cases some can be interchanged the best practice is to identify how your certificate is encoded and then label it correctly.  Correctly labeled certificates will be much easier to manipulat

Encodings (also used as extensions)

• .DER = The DER extension is used for binary DER encoded certificates. These files may also bear the CER or the CRT extension.   Proper English usage would be “I have a DER encoded certificate” not “I have a DER certificate”.
• .PEM = The PEM extension is used for different types of X.509v3 files which contain ASCII (Base64) armored data prefixed with a “—– BEGIN …” line.

Common Extensions

• .CRT = The CRT extension is used for certificates. The certificates may be encoded as binary DER or as ASCII PEM. The CER and CRT extensions are nearly synonymous.  Most common among *nix systems
• CER = alternate form of .crt (Microsoft Convention) You can use MS to convert .crt to .cer (.both DER encoded .cer, or base64[PEM] encoded .cer)  The .cer file extension is also recognized by IE as a command to run a MS cryptoAPI command (specifically rundll32.exe cryptext.dll,CryptExtOpenCER) which displays a dialogue for importing and/or viewing certificate contents.
• .KEY = The KEY extension is used both for public and private PKCS#8 keys. The keys may be encoded as binary DER or as ASCII PEM.

The only time CRT and CER can safely be interchanged is when the encoding type can be identical.  (ie  PEM encoded CRT = PEM encoded CER)

Common OpenSSL Certificate Manipulations

There are four basic types of certificate manipulations. View, Transform, Combination , and Extraction

View

Even though PEM encoded certificates are ASCII they are not human readable.  Here are some commands that will let you output the contents of a certificate in human readable form;

View PEM encoded certificate

Use the command that has the extension of your certificate replacing cert.xxx with the name of your certificate

openssl x509 -in cert.pem -text -noout
openssl x509 -in cert.cer -text -noout
openssl x509 -in cert.crt -text -noout

If you get the folowing error it means that you are trying to view a DER encoded certifciate and need to use the commands in the “View DER encoded certificate  below”

unable to load certificate
12626:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:647:Expecting: TRUSTED CERTIFICATE

View DER encoded Certificate

openssl x509 -in certificate.der -inform der -text -noout

If you get the following error it means that you are trying to view a PEM encoded certificate with a command meant for DER encoded certs. Use a command in the “View PEM encoded certificate above

unable to load certificate
13978:error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag:tasn_dec.c:1306:
13978:error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error:tasn_dec.c:380:Type=X509

Transform

Transforms can take one type of encoded certificate to another. (ie. PEM To DER conversion)

PEM to DER

openssl x509 -in cert.crt -outform der -out cert.der

DER to PEM

openssl x509 -in cert.crt -inform der -outform pem -out cert.pem

Combination

In some cases it is advantageous to combine multiple pieces of the X.509 infrastructure into a single file.  One common example would be to combine both the private key and public key into the same certificate.

The easiest way to combine certs keys and chains is to convert each to a PEM encoded certificate then simple copy the contents of each file into a new file.   This is suitable for combining files to use in applications lie Apache.

Extraction

Some certs will come in a combined form.  Where one file can contain any one of: Certificate, Private Key, Public Key, Signed Certificate, Certificate Authority (CA), and/or Authority Chain.

MANY THANKS:

SOURCE: http://www.gtopia.org/blog/2010/02/der-vs-crt-vs-cer-vs-pem-certificates/

http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html
Greg O’Keefe, gcokeefe@postoffice.utas.edu.au