How to use and exit minicom ?
2018-10-24
minicom -s (this is to configure the terminal) to exit minicom Press Ctrl – A , select Z , select XRead More →
Cisco networking : access-list and access-class
2018-10-23
When we apply an access-list to our router/switch, take this note: To apply an access list to a virtual terminal interface we must use the “access-class” command. This is used when we want to limit the access to our management interface. To apply an access list to a physical interface, we must use the “access-group” command.Read More →
Cisco Router: block ping from internet
2018-10-23
Let say we have a router , it’s connected to internet via interface Fa0/1. For security reason, we don’t want internet use to ping our router. We need to disable icmp , this could be done through access list. Router#conf t Router(config)#ip access-list extended acl-internet-in Router(config)#deny icmp any any echo Router(config)#permit ip any any Router(config)#end Then we need to apply this access list to our internet interface : Fa/01 Router#conf t Router(config)#int fa0/1 Router(config)#ip access-list acl-internet-in in Router(config)#end Read More →
ntc – tempalates :cisco_ios_show_mac-address-table.template
2018-10-10
#add this line in Type 3 – ^${VLAN}\s+${DESTINATION_ADDRESS}\s+${TYPE}\s+\S+\s+${DESTINATION_PORT} -> Record Value DESTINATION_ADDRESS (\w+.\w+.\w+) Value TYPE (\w+) Value VLAN (\w+) Value DESTINATION_PORT (\S+) Start ^Destination\s+Address\s+Address\s+Type\s+VLAN\s+Destination\s+Port -> TYPE1 ^\s+vlan\s+mac address\s+type\s+learn\s+age\s+ports -> TYPE2 ^\s+vlan\s+mac address\s+type\s+protocols\s+port -> TYPE3 ^Vlan\s+Mac Address\s+Type\s+Ports -> TYPE4 TYPE1 ^${DESTINATION_ADDRESS}\s+${TYPE}\s+${VLAN}\s+${DESTINATION_PORT} -> Record TYPE2 ^[\*|\s]\s+${VLAN}\s+${DESTINATION_ADDRESS}\s+${TYPE}\s+\S+\s+\S+\s+${DESTINATION_PORT} -> Record TYPE3 ^\s+${VLAN}\s+${DESTINATION_ADDRESS}\s+${TYPE}\s+\S+\s+${DESTINATION_PORT} -> Record ^${VLAN}\s+${DESTINATION_ADDRESS}\s+${TYPE}\s+\S+\s+${DESTINATION_PORT} -> Record TYPE4 ^\s+${VLAN}\s+${DESTINATION_ADDRESS}\s+${TYPE}\s+${DESTINATION_PORT} -> Record Read More →
Nagios: Sorry, but Nagios is currently not checking for external commands, so your command will not be committed!
2018-09-27
When you tried to stop Nagios to monitor some services from web interfaces – you see the message below: Sorry, but Nagios is currently not checking for external commands, so your command will not be committed! This is because we haven’t enable this feature in our configuration, it’s easy to fix. Open your nagios config file , /etc/nagios3/nagios.cfg Look for this line: check_external_commands=0 change it to check_external_commands=1 and reload nagios /etc/init.d/nagios3 restart You might receive this error: Error: Could not stat() command file ‘/var/lib/nagios3/rw/nagios.cmd’!. The fix is # /etc/init.d/nagios3 stop Stopping nagios3 monitoring daemon: nagios3Waiting for nagios3 daemon to die… . # dpkg-statoverride –updateRead More →
Mysql to Postgres – column header in query – it’s all in lower case
2018-09-19
By default when we run an query in postgres sql (psql) , all the table header is in lowercase , this is different with mysql. To keep the header as you want you have to put the column name in ” for example: select firstname as “FirstName” , LastName as “LastName” from users Read More →
/usr/bin/python^M: bad interpreter: No such file or directory
2018-09-19
it’s because the new line difference between Unix and windows , the easiest fix it run this command dos2unix filename Read More →
WordPress is slow: wp-captcha-booster – tech-banker-service
2018-09-13
I just found out that i could not access my wordpress today, i checked the server, everything looked good. i restarted the server, it’s still slow, there is no error. I decided to do a debug using the following command: cd /www/myswebsite.com/httpdocs/ strace php index.php I see my script stopped at sendmmsg(6, {{{msg_name(0)=NULL, msg_iov(1)=[{“-\265\1\0\0\1\0\0\0\0\0\0\24tech-banker-service”…, 42}], msg_controllen=0, msg_flags=MSG_DONTROUTE|MSG_DONTWAIT|MSG_FIN|MSG_SYN|MSG_ERRQUEUE|MSG_NOSIGNAL|MSG_FASTOPEN|0x6a80010}, 42}, {{msg_name(0)=NULL, msg_iov(1)=[{“\207E\1\0\0\1\0\0\0\0\0\0\24tech-banker-service”…, 42}], msg_controllen=0, msg_flags=MSG_OOB|MSG_DONTROUTE|MSG_CTRUNC|0x10}, 42}}, 2, MSG_NOSIGNAL) = 2 poll([{fd=6, events=POLLIN}], 1, 5000) = 1 ([{fd=6, revents=POLLIN}]) ioctl(6, FIONREAD, [58]) = 0 recvfrom(6, “-\265\201\200\0\1\0\1\0\0\0\0\24tech-banker-service”…, 2048, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr(“213.133.99.99”)}, [16]) = 58 poll([{fd=6, events=POLLIN}], 1, 4999) = 1 ([{fd=6, revents=POLLIN}]) ioctl(6, FIONREAD, [135]) = 0 recvfrom(6,Read More →
Linux: crontab syntax check
2018-09-09
The folder /etc/cron.d/ is used to store all cronjobs, the cronjob is saved on the file , the format is: minute hour day month dayofweek username command_to_run. There might some problems – the syntax is not correct , and the result is that the whole file will be ignore. I don’t know how to check the syntax , but i can watch to the syslog to see if there is any error. After we edit the file in crontab , the system will reload the cronjob, if there is any error it will throw an error in syslog. So i setup this before editing theRead More →
Ubuntu: Check disk heath – smartctrl and smartmontools
2018-08-26
smartctl is a nice tool to check your hard disk health – it will let you know how many hours your disk have been running , the hard disk serial number, temperature … by default smartctl is not installed by default, it’s in smartmontools package. To make it ready to use, you must install smartmontools apt-get install smartmontools After you install smartmontools you can run this command to check your hard disk health: smartctl –xall /dev/sda Here is a sample: smartctl 6.5 2016-01-24 r4214 [x86_64-linux-4.4.0-28-generic] (local build) Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org === START OF INFORMATION SECTION === Model Family: Toshiba 3.5″Read More →