Linux : small tips : blkid command

blkid command is a tool to display a UUID of block devices.

[ usage examples ]

Here’s /etc/fstab of my Fedora 16 machine.

# egrep -v ^# /etc/fstab | egrep -v ^$ UUID=ba2b7a10-73a2-4986-bcc5-964966fea960 /                       btrfs   defaults        1 1 UUID=0f9153b2-3a0a-472c-8766-d0a37755cbef swap                    swap    defaults        0 0

convert UUID to device name

[root@fc16 ~]# blkid -U ba2b7a10-73a2-4986-bcc5-964966fea960 /dev/sda1 [root@fc16 ~]# blkid -U 0f9153b2-3a0a-472c-8766-d0a37755cbef /dev/sda2

list UUID , file system type

[root@fc16 ~]# blkid /dev/sda1: UUID="ba2b7a10-73a2-4986-bcc5-964966fea960" UUID_SUB="d9f471c2-b4f9-400b-a604-aa0cb354b2b6" TYPE="btrfs" /dev/sda2: UUID="0f9153b2-3a0a-472c-8766-d0a37755cbef" TYPE="swap" /dev/sda5: UUID="eaf9e7cd-a2b7-4cb0-b589-ca3fb7f8c735" TYPE="swap" /dev/sda6: UUID="b3a1ec63-246c-4711-b0ba-b14584205b71" TYPE="ext4" /dev/sda7: UUID="5b301504-1784-418d-9c4f-1a48fdb37b22" TYPE="swap" /dev/sdb1: UUID="a8ad29b7-93d9-4fbd-8ae0-977d2dc3f2e8" TYPE="ext4" /dev/sdb2: UUID="7895c59c-8615-45bd-bb8d-164afb63dc26" UUID_SUB="f1271eaa-5dd2-44ab-9817-f72910ad50b0" TYPE="btrfs"

see the detailed info of block device

[root@fc16 ~]# blkid -p /dev/sda1 /dev/sda1: UUID="ba2b7a10-73a2-4986-bcc5-964966fea960" UUID_SUB="d9f471c2-b4f9-400b-a604-aa0cb354b2b6" TYPE="btrfs" USAGE="filesystem" PART_ENTRY_SCHEME="dos" PART_ENTRY_TYPE="0x83" PART_ENTRY_FLAGS="0x80" PART_ENTRY_NUMBER="1" PART_ENTRY_OFFSET="2048" PART_ENTRY_SIZE="286720000" PART_ENTRY_DISK="8:0"

edit /etc/fstab to mount /dev/sdb2 on a directory ( /var/Fedora16_USB_HDD ) when booting Fedora.

check UUID of /dev/sdb2

[root@fc16 ~]# blkid /dev/sdb2 /dev/sdb2: UUID="7895c59c-8615-45bd-bb8d-164afb63dc26" UUID_SUB="f1271eaa-5dd2-44ab-9817-f72910ad50b0" TYPE="btrfs"

edit /etc/fstab. add a red line.

[root@fc16 ~]# egrep -v ^# /etc/fstab UUID=ba2b7a10-73a2-4986-bcc5-964966fea960 /                       btrfs   defaults        1 1 UUID=0f9153b2-3a0a-472c-8766-d0a37755cbef swap                    swap    defaults        0 0 UUID=7895c59c-8615-45bd-bb8d-164afb63dc26 /var/Fedora16_USB_HDD   btrfs   defaults 0 0

reboot Fedora16 to confirm /dev/sdb2 is mounted on /var/Fedora16_USB_HDD directory when booting.

after rebooting Fedora.

[root@fc16 ~]# egrep sdb /etc/mtab /dev/sdb2 /var/Fedora16_USB_HDD btrfs rw,seclabel,relatime,nospace_cache 0 0

BIG-IP LTM VE : How to decrypt SSL traffic on LTM with ssldump

Here’s an explanation of how to decrypt SSL traffic with ssldump which has been installed on LTM devices.

Network topology

Client – vSW – LTM – vSW – Server*2

Client , LTM and two Servers are running on ESXi.

[root@ltm1:Active] ~ # b version | head -5 Kernel: Linux 2.6.18-164.2.1.el5.1.0.f5app Package: BIG-IP Version 10.1.0 3341.1084 Final Edition

[ create Virtual Servers for HTTPS ]

Before creating a Virtual Server for HTTPS , create Nodes and Pools.

Here’s a Vitual Server for HTTPS

Choose “clientssl” , which has been install on LTM by default , as SSL Profile (Client)

bigip.conf

node 192.168.0.100 {   monitor icmp   screen s1-ipv4 } node 192.168.0.101 {   monitor icmp   screen s2-ipv4 } pool http-ipv4 {   monitor all http   members {      192.168.0.100:http {}      192.168.0.101:http {}   } } virtual vs-https {   pool http-ipv4   destination 10.0.0.100:https   ip protocol tcp   persist cookie   profiles {      clientssl {         clientside      }      http {}      tcp {}   } }

[ access to the VIP from a client ]

confirm that you could access to the VIP.

[ ssldump on LTM ]

ssldump has been installed on LTM by default.

Please note that you could decrypt SSL traffic under the following conditions.

ssldump  can  decrypt traffic between two hosts if the following       two conditions are met:              1. ssldump has the keys.              2. Static RSA was used.

private key of “clientssl” profile is stored under /config/ssl/ssl.key directory.

[root@ltm1:Active] ~ # ssldump -k /config/ssl/ssl.key/default.key -i 1.1 port 443 -A -d    New TCP connection #1: 10.0.0.10(42572) <-> 10.0.0.100(443) 1 1  0.0011 (0.0011)  C>SV3.1(89)  Handshake      ClientHello        Version 3.1        random[32]=          4f 26 54 e3 a8 e1 a4 d4 a0 8c c1 11 ad a2 fe cb          c9 7f 3d ff 4b 58 65 6c 1c 28 c9 2c 4e 88 de 8c        cipher suites        Unknown value 0xff        Unknown value 0x88        Unknown value 0x87        TLS_DHE_RSA_WITH_AES_256_CBC_SHA        TLS_DHE_DSS_WITH_AES_256_CBC_SHA        Unknown value 0x84        TLS_RSA_WITH_AES_256_CBC_SHA        Unknown value 0x45        Unknown value 0x44        TLS_DHE_RSA_WITH_AES_128_CBC_SHA        TLS_DHE_DSS_WITH_AES_128_CBC_SHA        Unknown value 0x96        Unknown value 0x41        TLS_RSA_WITH_RC4_128_MD5        TLS_RSA_WITH_RC4_128_SHA        TLS_RSA_WITH_AES_128_CBC_SHA        TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA        TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA        Unknown value 0xfeff        TLS_RSA_WITH_3DES_EDE_CBC_SHA        compression methods                  NULL 1 2  0.0013 (0.0002)  S>CV3.1(48)  Handshake      ServerHello        Version 3.1        random[32]=          4f 26 54 e3 99 85 29 14 f9 26 a2 a2 0d 68 7f 6e          ae 49 2d 4c d0 3b af d4 7d 67 ff 83 a1 77 a3 9e        session_id[0]=        cipherSuite         TLS_RSA_WITH_AES_256_CBC_SHA        compressionMethod                   NULL 1 3  0.0013 (0.0000)  S>CV3.1(692)  Handshake      Certificate 1 4  0.0013 (0.0000)  S>CV3.1(4)  Handshake      ServerHelloDone 1 5  0.0375 (0.0362)  C>SV3.1(134)  Handshake      ClientKeyExchange        EncryptedPreMasterSecret[128]=          15 b1 e0 a9 db 90 19 49 12 82 3b e4 60 cd bf eb          5d 6a fe 05 67 05 19 1f 07 1b 8d 0d ce 9e d4 0d          2d 90 92 1a c8 5e 5d 57 18 b0 03 53 ad 19 a8 a1          17 33 e0 25 30 71 3d 30 7e 07 67 ba c3 f4 ee 36          6e d8 8a 42 5d 34 cc d1 82 30 ed 5a dc 4c 3f df          9a 9b ed 53 a6 2c 62 9b b8 0f 72 43 02 a8 1c 60          e5 aa 69 4a c7 b1 74 28 93 cb 1d dd 65 58 00 41          2a 75 fb 33 17 32 59 3f ca 35 52 54 aa 95 d3 a1 1 6  0.0375 (0.0000)  C>SV3.1(1)  ChangeCipherSpec 1 7  0.0375 (0.0000)  C>SV3.1(48)  Handshake      Finished        verify_data[12]=          97 48 73 91 a0 ea 37 d4 74 c8 9c c4 1 8  0.0408 (0.0033)  S>CV3.1(170)  Handshake 1 9  0.0408 (0.0000)  S>CV3.1(1)  ChangeCipherSpec 1 10 0.0408 (0.0000)  S>CV3.1(48)  Handshake      Finished        verify_data[12]=          8c 91 bd e5 93 c4 36 34 80 53 49 24 1 11 0.0419 (0.0011)  C>SV3.1(416)  application_data    ---------------------------------------------------------------    GET / HTTP/1.1    Host: 10.0.0.100    User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.24) Gecko/20111108 Red Hat/3.6.24-3.el6_1 Firefox/3.6.24    Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8    Accept-Language: en-us,en;q=0.5    Accept-Encoding: gzip,deflate    Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7    Keep-Alive: 115    Connection: keep-alive        --------------------------------------------------------------- 1 12 0.0443 (0.0023)  S>CV3.1(352)  application_data    ---------------------------------------------------------------    HTTP/1.1 200 OK    Date: Mon, 30 Jan 2012 08:29:23 GMT    Server: Apache/2.2.15 (Scientific Linux)    Last-Modified: Mon, 05 Sep 2011 05:55:49 GMT    ETag: "443e5-6-4ac2b5ce8a846"    Accept-Ranges: bytes    Content-Length: 6    Connection: close    Content-Type: text/html; charset=UTF-8    Set-Cookie: lbcookie=1694542016.20480.0000; path=/        --------------------------------------------------------------- 1 13 0.0443 (0.0000)  S>CV3.1(32)  application_data    ---------------------------------------------------------------    SL6-3    --------------------------------------------------------------- 1    0.0443 (0.0000)  S>C  TCP FIN 1 14 0.0454 (0.0010)  C>SV3.1(32)  Alert    level           warning    value           close_notify 1    0.0486 (0.0032)  C>S  TCP FIN New TCP connection #2: 10.0.0.10(42573) <-> 10.0.0.100(443) 2 1  0.0011 (0.0011)  C>SV3.1(281)  Handshake      ClientHello        Version 3.1        random[32]=          4f 26 54 e4 7e 4a 05 b5 ea f1 20 6c 13 39 a8 bf          91 b9 6f 4b 19 a9 d1 d4 26 ee d1 45 a6 1a 5a b7        resume [32]=          b0 f9 74 fb 02 41 00 40 e8 28 b5 85 b5 5f 0b c9          ed 7d 2f 7d 6c d1 78 37 e4 08 6d bf ca 22 22 2f        cipher suites        Unknown value 0xff        Unknown value 0x88        Unknown value 0x87        TLS_DHE_RSA_WITH_AES_256_CBC_SHA        TLS_DHE_DSS_WITH_AES_256_CBC_SHA        Unknown value 0x84        TLS_RSA_WITH_AES_256_CBC_SHA        Unknown value 0x45        Unknown value 0x44        TLS_DHE_RSA_WITH_AES_128_CBC_SHA        TLS_DHE_DSS_WITH_AES_128_CBC_SHA        Unknown value 0x96        Unknown value 0x41        TLS_RSA_WITH_RC4_128_MD5        TLS_RSA_WITH_RC4_128_SHA        TLS_RSA_WITH_AES_128_CBC_SHA        TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA        TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA        Unknown value 0xfeff        TLS_RSA_WITH_3DES_EDE_CBC_SHA        compression methods                  NULL 2    28.1854 (28.1842)  C>S  TCP FIN 2    28.1854 (0.0000)  S>C  TCP FIN New TCP connection #3: 10.0.0.10(42574) <-> 10.0.0.100(443) 3 1  0.0011 (0.0011)  C>SV3.1(281)  Handshake      ClientHello        Version 3.1        random[32]=          4f 26 54 ff c4 f5 10 80 9d 56 2d 64 66 e0 ff 29          56 04 bf 1b 03 f6 5a 5e d0 25 c5 fc 1d 0b 69 d4        resume [32]=          b0 f9 74 fb 02 41 00 40 e8 28 b5 85 b5 5f 0b c9          ed 7d 2f 7d 6c d1 78 37 e4 08 6d bf ca 22 22 2f        cipher suites        Unknown value 0xff        Unknown value 0x88        Unknown value 0x87        TLS_DHE_RSA_WITH_AES_256_CBC_SHA        TLS_DHE_DSS_WITH_AES_256_CBC_SHA        Unknown value 0x84        TLS_RSA_WITH_AES_256_CBC_SHA        Unknown value 0x45        Unknown value 0x44        TLS_DHE_RSA_WITH_AES_128_CBC_SHA        TLS_DHE_DSS_WITH_AES_128_CBC_SHA        Unknown value 0x96        Unknown value 0x41        TLS_RSA_WITH_RC4_128_MD5        TLS_RSA_WITH_RC4_128_SHA        TLS_RSA_WITH_AES_128_CBC_SHA        TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA        TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA        Unknown value 0xfeff        TLS_RSA_WITH_3DES_EDE_CBC_SHA        compression methods                  NULL [root@ltm1:Active] ~ #

Fedora 16 : set up FreeNX server and connect to Linux machines from Windows through NX session

Here’s an explanation of how to set up FreeNX server on Fedora16.

[root@fc16 ~]# cat /etc/redhat-release Fedora release 16 (Verne) [root@fc16 ~]# uname -ri 3.2.1-3.fc16.i686.PAE i386 # /usr/libexec/nx/nxserver --list NX> 100 NXSERVER - Version 3.2.0-74-SVN OS (GPL, using backend: 3.5.0)

Windows7 ( FreeNX Client ) --- Fedora16 ( FreeNX Server )

[ install FreeNX Server ]

install FreeNX server via yum.

[root@fc16 ~]# yum install -y freenx-server

set up the FreeNX server

[root@fc16 ~]# nxsetup --install --setup-nomachine-key Setting up /etc/nxserver ...done Generating public/private dsa key pair. Your identification has been saved in /etc/nxserver/users.id_dsa. Your public key has been saved in /etc/nxserver/users.id_dsa.pub. The key fingerprint is: The key's randomart image is: Setting up /var/lib/nxserver/db ...done Setting up /var/log/nx/nxserver.log ...done Adding user "nx" to group "utmp" ...done Setting up known_hosts and authorized_keys2 ...done Setting up permissions ...done Setting up cups nxipp backend ...done

edit node.conf

[root@fc16 sessions]# egrep -v ^# /etc/nxserver/node.conf | egrep -v ^$ ENABLE_PASSDB_AUTHENTICATION="0" ENABLE_SSH_AUTHENTICATION="1" ENABLE_CLIPBOARD="both" NX_LOG_LEVEL=4 COMMAND_START_GNOME="/usr/bin/gnome-session --session=gnome-fallback"

In my case , I can’t access to the Fedora with GNOME3 though NX session.
I can use GNOME3 when logging on the Fedora machine locally.
I changed “COMMAND_START_CNOME” option from “gnome-session” to “gnome-session --session=gnome=fallback”  to fallback to classic gnome style from GNOME3 style through NX session.

change COMMAND_START_GNOME option

from

COMMAND_START_GNOME=gnome-session

to

COMMAND_START_GNOME="/usr/bin/gnome-session --session=gnome-fallback"

You could find what kind of options you could specify as the  “--session=” option by checking /usr/share/gnome-session/sessions directory.

# ls /usr/share/gnome-session/sessions/ gdm-fallback.session  gdm-shell.session  gnome-fallback.session  gnome.session

In that case , I can use --session=gdm-fallback or gdm-shell or gnome-fallback or gnome.

start freenx-server

[root@fc16 ~]# systemctl start freenx-server.service [root@fc16 ~]# systemctl status freenx-server.service freenx-server.service - FreeNX Server          Loaded: loaded (/lib/systemd/system/freenx-server.service; disabled)          Active: active (exited) since Sat, 28 Jan 2012 16:59:02 +0900; 6s ago         Process: 4729 ExecStart=/usr/libexec/nx/nxserver --start (code=exited, status=0/SUCCESS)         Process: 4656 ExecStartPre=/usr/libexec/nx/nxserver --cleanup (code=exited, status=1/FAILURE)          CGroup: name=systemd:/system/freenx-server.service

make .Xmodmap for keyboaad mapping settings.

# xmodmap -pke > /home/user/.Xmodmap # chown user.user /home/user/.Xmodmap

edit .Xmodmap to correct the keyboard mappings.

change keycode 123:

from

keycode 123 = XF86AudioRaiseVolume NoSymbol XF86AudioRaiseVolume

to

keycode 123 = backslash underscore

change keycode 133

from

keycode 133 = Super_L NoSymbol Super_L

to

keycode 133 = backslash bar backslash bar

You can check key codes by xev command.


[ NX client ]

Download NX client from http://www.nomachine.com/download.php.

launch NXClient and configure an NX session to access to the Fedora16 notebook like this:



edit the NX client configuration to use Japanese keyboard layout.

open *.nxs file with text editor
In my case , nxs files are stored under C:\Users\username\.nx\config folder.

add keyboard layout ( Fedora16 notebook.nxs )

<option key="Custom keyboard layout" value="jp" />

If your keyboard layout is still wrong even though you edited .Xmodmap file and nxs file ( NX client configuration) correctly , you might also check the keyboard layout of i-Bus settings via NX session.


To start freenx-server when booting the Fedora.

# systemctl enable freenx-server.service ln -s '/lib/systemd/system/freenx-server.service' '/etc/systemd/system/multi-user.target.wants/freenx-server.service'

# /usr/libexec/nx/nxserver --list NX> 100 NXSERVER - Version 3.2.0-74-SVN OS (GPL, using backend: 3.5.0) NX> 127 Sessions list: Server     Display Username        Remote IP       Session ID ------ ------- --------------- --------------- -------------------------------- 127.0.0.1       2000    zzzz 192.168.11.5    zzzzzzzzzzzzzzzzzzzzzzzzz NX> 999 Bye