Linux–Unix VI Search en replace
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- Mar, 12, 2011
- Angelo Schalley
- Linux
Vi: Search and Replace
Change to normal mode with <ESC>.
Search (Wraped around at end of file):
Search STRING forward : / STRING. Search STRING backward: ? STRING. Repeat search: n Repeat search in opposite direction: N (SHIFT-n)
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Webserver behind a router – firewall – apache – linux
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- Mar, 11, 2011
- Angelo Schalley
- Linux, Networking, security
Web Server Set Up – Dynamic or Static IP
Apache Web Server configuration for Redhat 7.3, 8.0 and 9.0 with Dynamic ip to router.
This section is designed to detail the steps you may need to go through to setup a server on an ISP that only gives out a dynamic IP address. You will need to edit network configuration on your server by set it to statically and taking the ip number you’ve been assigned by your router (eg) – (192.168.0.2), subnet mask 255.255.255.0 and gateway 192.168.0.1, and use your isp nameservers ip’s. The general approach is to use a dynamic ip address yet access your server via a domain name. This allows you and others to always reach your website from the outside even if the ip address changes regularly. Basically what needs to be done is to configure the apache configuration file httpd.conf for your dynamic IP.
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Unicast vs Broadcast vs Multicast
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- Feb, 05, 2011
- Angelo Schalley
- Cisco, Networking
Unicast
Unicast packets are sent from host to host. The communication is from a single host to another single host. There is one device transmitting a message destined for one reciever.
Broadcast
Broadcast is when a single device is transmitting a message to all other devices in a given address range. This broadcast could reach all hosts on the subnet, all subnets, or all hosts on all subnets. Broadcast packets have the host (and/or subnet) portion of the address set to all ones. By design, most modern routers will block IP broadcast traffic and restrict it to the local subnet.
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