Traditional “sendmail -q” command flushes mail queue. Under Postfix,
just enter the following to flush the mail queue
# postfix flush
OR
# postfix -f
To see mail queue, enter:
# mailq
To remove all mail from the queue, enter:
# postsuper -d ALL
To remove all mails in the deferred queue, enter:
# postsuper -d ALL deferred
By Vincent Danen
With Apache 2.2.12 and support for the Server Name Indication extension to the SSL protocol, you can configure name-based HTTPS sites, just as you
can name-based HTTP sites.
As the Apache Web server grows and matures, new features are added and old bugs are fixed. Perhaps one of the most important new features added to
recent Apache versions (2.2.12, to be specific) is the long-awaited support for multiple SSL sites on a single IP address.
OpenSSH version 4.3 introduced a new feature: the ability to create on-the-fly “Virtual Private Networks” via the tunnel driver (the so-called “tun” driver). This allows you to create a network interface that bridges two physically disparate network segments in different locations. This article explains how to use SSH to set up SSH-based point to point connections with OpenSuse 11.0 which can then be used to create routes that create virtual private networks.
This post assumes you are running some form of UNIX on your machine (Linux, Solaris, BSD, OS X, …). If you’re not, you have my sympathy. Any Internet-connected computer needs a DNS server. Typically your ISP will provide this. You quite likely don’t even need to know how to communicate with the DNS server; if you are using DHCP to get your host configuration it will be set up automatically. However, it can sometimes be advantageous to do a bit of the work yourself. The most effective method of improving your DNS performance is to install a cache on your local machine.
General Information
This guide details how to set up user accounts with disk allocation. Let’s say you want to limit each user to a specific size disk usage — 100 megs each. You will need to set “user quotas.” Here we go!!
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Bonding is creation of a single bonded interface by combining 2 or more ethernet interfaces. This helps in high availability and performance improvement.
Steps for bonding in Fedora Core and Redhat Linux
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[root@unixfoo root]# cat /proc/meminfo
total: used: free: shared: buffers: cached:
Mem: 8298250240 2093281280 6204968960 0 177729536 1242714112
Swap: 17174069248 0 17174069248
MemTotal: 8103760 kB
MemFree: 6059540 kB
MemShared: 0 kB
If you want to force fsck on the next boot, just create a file called /forcefsck . If this file is present, then during next boot - the fsck is forced.
# touch /forcefsck
Now reboot the machine and when it comes up, fsck will be forced.
# reboot
http://unixfoo.blogspot.com/
Tunable TCP settings can be found on /proc/sys/net/ipv4 . Here are the details of few of them.
tcp_keepalive_probes : Number of KEEPALIVE probes tcp sends out, until the server decides that the connection is
broken.
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Firewalls are an useful way of adding some security to your system, but they are not a panacea. A properly configured firewall can make it much harder to break into your system, and in some cases can even protect you from mistakes or misconfigurations elsewhere in the system, but should not be viewed as the sole, or even the main, defense against hacking, but merely one of a system of defenses. Regular and frequent patching and updates are still essential.