Visit Our UNIX and Linux User Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #56
Difficulty: Easy
A flip-flop circuit stores 1 bit of data.
True or False?
Linux & Unix Commands - Search Man Pages

synos(1) [bsd man page]

synos(1)							Mail Avenger 0.8.3							  synos(1)

NAME
synos - guess operating system from TCP SYN fingerprint SYNOPSIS
synos [--mtu mtu] [--db path] syn-fingerprint DESCRIPTION
synos takes a SYN fingerprint, in the format described for the CLIENT_SYNFP environment variable in the avenger(1) man page, and outputs a guess as to the type of the client operating system. synos makes use of the OpenBSD SYN fingerprint database (which is also repackaged with Mail Avenger). OPTIONS --mtu val Certain operating systems set the initial TCP window size based on the maximum transmission unit, or MTU, of the network. For such operating systems, synos usually checks the window size using both the client's MSS option plus 40 bytes (for TCP and IP headers), or a hard-coded MTU, which defaults to 1,500 bytes. If either value works, the fingerprint is considered to match the operating system. You can change the value 1,500 by specifying this option. A value of 0 tells synos to use only the value derived from the MSS option. --db file Specifies an alternate location for the SYN fingerprint database. FILES
/usr/local/share/pf.os Default location of SYN fingerprint database. SEE ALSO
avenger(1), asmtpd(8) The Mail Avenger home page: <http://www.mailavenger.org/>. The OpenBSD home page: <http://www.openbsd.org/>. BUGS
The operating system type is determined by heuristics that are not always reliable. Moreover, not all operating systems can be distinguished. The database may not even contain a client's particular operating system and version. It is not hard to fool synos deliberately by changing TCP socket options or injecting raw packets onto the network. AUTHOR
David Mazieres Mail Avenger 0.8.3 2012-04-05 synos(1)

Check Out this Related Man Page

synos(1)							Mail Avenger 0.8.3							  synos(1)

NAME
synos - guess operating system from TCP SYN fingerprint SYNOPSIS
synos [--mtu mtu] [--db path] syn-fingerprint DESCRIPTION
synos takes a SYN fingerprint, in the format described for the CLIENT_SYNFP environment variable in the avenger(1) man page, and outputs a guess as to the type of the client operating system. synos makes use of the OpenBSD SYN fingerprint database (which is also repackaged with Mail Avenger). OPTIONS --mtu val Certain operating systems set the initial TCP window size based on the maximum transmission unit, or MTU, of the network. For such operating systems, synos usually checks the window size using both the client's MSS option plus 40 bytes (for TCP and IP headers), or a hard-coded MTU, which defaults to 1,500 bytes. If either value works, the fingerprint is considered to match the operating system. You can change the value 1,500 by specifying this option. A value of 0 tells synos to use only the value derived from the MSS option. --db file Specifies an alternate location for the SYN fingerprint database. FILES
/usr/local/share/pf.os Default location of SYN fingerprint database. SEE ALSO
avenger(1), asmtpd(8) The Mail Avenger home page: <http://www.mailavenger.org/>. The OpenBSD home page: <http://www.openbsd.org/>. BUGS
The operating system type is determined by heuristics that are not always reliable. Moreover, not all operating systems can be distinguished. The database may not even contain a client's particular operating system and version. It is not hard to fool synos deliberately by changing TCP socket options or injecting raw packets onto the network. AUTHOR
David Mazieres Mail Avenger 0.8.3 2012-04-05 synos(1)

3 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Grep for the same occurrence or maybe Sed

Hi, I have a file that looks like this dasdjasdjoasjdoasjdoa SYN dakspodkapsdka asdasdasdasdasdasdasd SYN sdfsdfsdfsdfdf shfishifhsdifhsidhfif fsdfsdfsdfsdfs sdfsdfsdfsdsdfsdfsdff cercercercerce sdasdajsdoajsodasodoo FIN dasdaskdpasdda... (4 Replies)
Discussion started by: hcclnoodles
4 Replies

2. Solaris

TCP SYN timer

Can anybody please tell me how I can figure out on a solaris server how long it would take a TCP SYN request to timeout before it gets a SYN_ACK back? Thanks, (3 Replies)
Discussion started by: Pouchie1
3 Replies

3. HP-UX

When MTU changed, system panic occured

Hello I have some hpux 11.23/31 systems ,and some other (linux,solaris) I know if i want change the mtu size ,need use lanadmin. But:if i try on 11.23 : ifconfig lan1 mtu 8000,system paniced. If i try on 11.31 :ifconfig lan1 mtu 8000,remove ip address from interface. Ithink is not a best... (1 Reply)
Discussion started by: zoldkalap
1 Replies

Featured Tech Videos