87
votes
4answers
10k views

Should I quit using Ifconfig?

With the servers that mount Infiniband cards, when I use the ifconfig command, I get this warning: Ifconfig uses the ioctl access method to get the full address information, which limits hardware ...
44
votes
2answers
49k views

SFTP logging: is there a way?

I'm wondering if there is a way to log commands received by the server. It can be all SSH commands, as long as it includes information on commands related to file transfer. I'm having issues with an ...
30
votes
16answers
28k views

Is Round-Robin DNS “good enough” for load balancing static content?

We have a set of shared, static content that we serve up between our websites at http://sstatic.net. Unfortunately, this content is not currently load balanced at all -- it's served from a single ...
54
votes
6answers
11k views

Heartbleed: are services other than HTTPS affected?

The OpenSSL 'heartbleed' vulnerability (CVE-2014-0160) affects webservers serving HTTPS. Other services also use OpenSSL. Are these services also vulnerable to heartbleed-like data leakage? I'm ...
44
votes
8answers
3k views

Why would I need a firewall if my server is well configured?

I admin a handful of cloud-based (VPS) servers for the company I work for. The servers are minimal ubuntu installs that run bits of LAMP stacks / inbound data collection (rsync). The data is large ...
16
votes
6answers
9k views

MySQL InnoDB - innodb_file_per_table cons?

By default MySQL InnoDB stores all tables of all DBs in one global file. You can change this by setting innodb_file_per_table in the config, which then creates one data file for each table. I am ...
25
votes
6answers
8k views

Meaning of directories on Unix and Unix like systems

I've been using Linux for a couple of years now but I still haven't figured out what the origin or meaning of some the directory names are on Unix and Unix like systems. E.g. what does etc stand for ...
22
votes
5answers
28k views

What is the difference between SAN, NAS and DAS?

What is the difference between SAN, NAS and DAS?
31
votes
5answers
3k views

What to look for in a server rack?

I'm looking to purchase a rack/enclosure for some servers. As this is my first time shopping for this type of equipment, I need to know what to look for. I'm asking not only about how to buy the rack, ...
25
votes
13answers
3k views

Server Hosting from your House - $200 to $300 per month range

I'm a developer lacking some infrastructure knowledge. What is the fattest pipe I can get to my house in the $200 to $300 range? I'd like to host a few servers at my house. Then if my company gets ...
19
votes
5answers
3k views

Unix Server Partitioning & Filesystem Layout

There's a lot of contradictory information about Unix server partitioning out on the internet, so I need some advice on how to proceed. So far, on the servers I in our test environment I didn't ...
25
votes
7answers
30k views

Apache Default/Catch-All Virtual Host?

If I have 3 domains, domain1.com, domain2.com, and domain3.com, is it possible to set up a default virtual host to domains not listed? For example, if I would have: <VirtualHost 192.168.1.2 ...
44
votes
8answers
42k views

Is a wildcard CNAME DNS record valid?

I know it's valid to have a DNS A record that's a wildcard (e.g. *.mysite.com). Is it possible/valid/advised to have a wildcard CNAME record?
23
votes
8answers
24k views

Will disabling hyperthreading improve performance on our SQL Server install

Related to: Current wisdom on SQL Server and Hyperthreading Recently we upgraded our Windows 2008 R2 database server from an X5470 to a X5560. The theory is both CPUs have very similar performance, ...
13
votes
10answers
24k views

How do I know if I am running 32 or 64-bit Linux?

what would be a command to run in different distros?
42
votes
6answers
32k views

Is X.Y.Z.0 a valid IP address?

Are IP addresses with a 0 in the last octet valid? 10.6.43.0 In my case, I have the the following netmask 255.255.252.0 What about a 0 for the other octets?
25
votes
8answers
21k views

Private IP address in public DNS

We have an SMTP only mail server behind a firewall which will have a public A record of mail.. The only way to access this mail server is from another server behind the same firewall. We do not run ...
15
votes
5answers
6k views

Log all commands run by admins on production servers

It is company policy for admins to login to the servers via a personal username, and then run sudo -i to become root. Upon running sudo -i, sudo will create an environmental variable called ...
30
votes
2answers
7k views

Why does Heroku warn against “naked” domain names?

I ran across this page in the Heroku docs... Naked domains, also called bare or apex domains, are configured in DNS via A-records and have serious availability implications when used in highly ...
12
votes
5answers
57k views

Huge amount of TIME_WAIT connections says netstat

Okay, this is creeping me out - I see about 1500-2500 of these: root@wherever:# netstat Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 ...
51
votes
10answers
7k views

Why drop caches in Linux?

In our servers we have a habit of dropping caches at midnight. sync; echo 3 > /proc/sys/vm/drop_caches When I run the code it seems to free up lots of RAM, but do I really need to do that. ...
14
votes
12answers
35k views

How do I know if I'm working on a Virtual Machine or not?

Is there a way to know if the Windows machine I'm working on is virtual or physical? (I'm connecting with RDP to the machine. If it's a virtual machine it is working and handled by VMWare).
10
votes
2answers
6k views

SSL site not using the correct IP in Apache and Ubuntu

I'm trying to set up an apache-ubuntu-php webserver. My webserver will host multiple SSL sites, each SSL site will have it's own IP address (unless there's a better way to do this). So I suppose the ...
14
votes
7answers
14k views

How to change “From:” field for emails from Cron?

I use remote SMTP via nullmailer and it requires set From field to the specific name, but cron set it as root@my.sweet.server.com. How could I change it to something like me@ya.ru?
6
votes
4answers
2k views

Rotate logs of a dumb non-interactive application

Ubuntu 10.4 Server. I have a dumb non-interactive legacy service which is running constantly on my server. It is writing its log to a file with fixed name (/var/log/something.log). It does not ...
4
votes
3answers
4k views

How to diagnose causes of oom-killer killing processes

I have a small virtual private server running CentOS and www/mail/db, which has recently had a couple of incidents where the web server and ssh became unresponsive. Looking at the logs, I saw that ...
2
votes
1answer
1k views

Setting up a Rails 2.3.x app on EC2 for easy scalability

I'm running a simple rails stack on a single dedicated machine. We're reaching our full capacity and have absolutely no setup for scaling, just one app on one machine. I did some research and came up ...
10
votes
9answers
25k views

NRPE unable to read output, but why?

I have this problem with NRPE, all the stuff I've found so far on the net seems to point me at things I've already tried. # /usr/local/nagios/plugins/check_nrpe -H nrpeclient gives NRPE v2.12 as ...
5
votes
6answers
25k views

Windows Event Log - email notification

Is there an easy way to send an email when a particular severity of event from a particular service hits the Windows server event log? This is on Windows Server 2003, if it makes a difference. n.b. ...
4
votes
5answers
2k views

Deep Format of a Harddrive on a Linux System

I've got an original Asus Eee PC Netbook that I'd like to sell. When I've sold old computers in the past, I've typically done a deep/secure/zeroing out style format. How can I do this on a Linux ...
13
votes
3answers
5k views

What happens when the USB key or SD card I've installed VMware ESXi on fails?

An SD (SDHC) card installed in an HP ProLiant DL380p Gen8 server running VMware ESXi just failed :( I encountered some ominous looking messages on the vCenter console and in the HP ProLiant ILO event ...
3
votes
4answers
4k views

HP D2700 enclosure and SSDs. Will any SSD work?

I've got an HP D2700 enclosure that I'm looking to shove some 2.5" SSD drives in. Looking at the prices of HP's SSD drives vs something like an Intel 710 and even something less 'enterprisey', there's ...
3
votes
3answers
4k views

simple rsync in crontab without password

I would like to run the following: (Centos 5.4) rsync -avz /source_folder 192.168.1.1:/destination_folder right now I'm running it from CLI but eventually I would like to run it from crontab ...
6
votes
2answers
1k views

SQL Server memory constantly going up, from 1GB RAM used to 7GB in a week

I have a ~45GB database that increases rapidly (~1GB every week). So it's doing a lot of inserts; the web app doesn't have many users so reads are low right now. But I'm noticing that the RAM sql ...
3
votes
3answers
26k views

chmod -R 777 / on ubuntu - numerous problems

A client has accidentally given the entire filesystem full permissions on their ubuntu 10.04 box. chmod -R 777 httpdocs/cd / As you can see they attempted to cd to the root, and instead gave chmod ...
2
votes
1answer
670 views

Server refuses to use swap partition

We are running a server with 23 cores (cpuinfo shows 22 as the highest process number) and 66 Gig RAM. The development team here is running some apps, which hogs memory. I have observered that: 1. ...
8
votes
1answer
256 views

Why can't a CNAME record be used at the apex of a domain?

It's relatively common knowledge that CNAME records at the apex of a domain are a taboo practice. Example: example.com. IN CNAME ithurts.example.net. In a best case scenario nameserver software ...
4
votes
2answers
285 views

Accidential CHMOD 755

Alright, I accidentially chomdded everything to 755, which isn't as terrible as chowning everything to the local user. How insecure is this and how would I restore it easily, without reinstalling?
2
votes
2answers
809 views

What do I need to parse incoming emails?

My intention is to parse incoming emails with PHP. What would be the simplest way to set this up? Would it suffice to rely on Postfix for this, or is there a better alternative? The purpose of the ...
1
vote
2answers
618 views

revert chmod 777 / -R

while executing a command i made a mistake and executed (ubuntu 10) sudo chmod 777 / -R # okay you may laugh now all my filesystem has 777 permitions , obviously i dont know which ...
0
votes
0answers
3k views

Aftermath of Hack

We recently faced a full scale attack on one of our servers running Open SUSE 11.0; the intruder deleted a lot of files necessary for day to day operation. Although the backups came in handy but for a ...
-3
votes
1answer
1k views

How do I open custom ports in my iptables firewall? [closed]

I need IPTables, like everyone else, but I don't use it enough to really keep my knowledge complete and fresh. The setup utility in CentOS is too basic. It doesn't seem to allow me to open up custom ...
142
votes
39answers
39k views

What useful things can one add to one's .bashrc? [closed]

Is there anything that you can't live without and will make my life SO much easier? Here are some that I use ('diskspace' & 'folders' are particularly handy). # some more ls aliases alias ll='ls ...
46
votes
9answers
62k views

What's the best way to move c:\users to d:\users under vista/W7 [closed]

I just installed Windows 7 RC1 and want to move c:\users to d:\users. What's the best way to do this? Due to the fact that Windows 7 creates a reserved partition that is mounted as C: in the ...
65
votes
8answers
147k views

How to automate SSH login with password?

How to automate SSH login with password? I'm configuring my test VM, so heavy security is not considered. SSH chosen for acceptable security with minimal configuration. ex) echo password | ssh ...
54
votes
5answers
14k views

Active Directory explained

If you had to explain Active Directory to someone how would you explain it?
33
votes
20answers
14k views

Storing a million images in the filesystem

I have a project that will generate a huge number of images. Around 1,000,000 for start. They are not large images so I will store them all on one machine at start. How do you recommended on ...
34
votes
3answers
54k views

Can IIS be configure to forward request to another web server?

I have several web site set up on one IIS 6 server distinguished by Host Header. However, I wish to have one of the sites served by a Linux / Apache server on my network. Do I need to use a reverse ...
29
votes
6answers
4k views

Automatically Configure New Computers

My company is in the process of upgrading all of our users from old Windows XP computers to newer quad-core Win7 computers. This is a good thing - it's long overdue that we upgrade our workstations - ...
22
votes
7answers
21k views

how can I limit per user bandwidth?

To summarise: I have a dedicated server with a few friends running a torrent client with web gui. Each user is running a client under their username on the server so downloads go in their user dir, ...

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