Greatest Hits

16
votes
5answers
46k views

where are the default ulimit values set? (linux, centos)

I have two CentOS (5) servers with nearly identical specs. When I login and do: ulimit -u on one machine, I get unlimited and on the other, 77824 When I run a cron like * * * * * ulimit ...
8
votes
9answers
57k views

psexec: “Access is Denied”?

Inspired by my previous question here, I've been experimenting with PSExec. The goal is to trip off some fairly simple scripts / programs on one WindowsXP machine from another, and as PowerShell 2 ...
13
votes
1answer
67k views

Where/how does Windows store the data in the event logs?

We run some financial systems that log error messages to the system logs. I need to find out if we can clean these error messages from a PCI DSS point of view. I am specificaly interested in the ...
4
votes
2answers
29k views

List All Groups and Their Members with PowerShell on Win2008r2

I am new to powershell, but I've been reading manuals and practiced a little bit. My objective is to List all users in all Security Groups under specified path. I have found the way to do it: ...
8
votes
5answers
100k views

Reverse DNS - how to correctly configure for SMTP delivery

I started a new service and we need to send emails to our customers (new account confirms, etc). My server is known as prod01.bidrodeo.com and resolves to 97.107.134.38 . For reverse DNS, ...
28
votes
9answers
81k views

Increase number of allowed remote desktop connections

Windows Server 2003 allows 2 non-console and one console remote desktop connections. Is there a way to increase the number of non-console sessions allowed?
34
votes
8answers
10k views

How can I run arbitrarily complex command using sudo over ssh?

I have a system that I can only log in to under my username (myuser), but I need to run commands as other user (scriptuser). So far, I have come up with the following to run the commands I need: ssh ...
29
votes
5answers
74k views

Why do we ping the IP 4.2.2.2 to test connectivity?

For as long as I can remember, I've always used the IP 4.2.2.2 when testing network connectivity using ping. What is significant about this IP, and when did this practice start?
22
votes
4answers
83k views

How to filter http traffic in Wireshark?

I suspect my server has a huge load of http requests from its clients. I want to measure the volume of http traffic. How can I do it with Wireshark? Or probably there is an alternative solution using ...
8
votes
7answers
63k views

“Error 1067: The process terminated unexpectedly” when trying to install MySQL on Win7 x64

I've run into a brick wall trying to install MySQL v5.5 on my machine. My PC is Windows 7 x64, Enterprise edition. MySQL installs fine, but when I run the "MySQL Instance Configuration Wizard", it ...
42
votes
7answers
51k views

mysqldump to a tar.gz

Usually after dumping a MySQL database with mysqldump command I immediately tar/gzip the resultant file. I'm looking for a way to do this in one command: So from this: mysqldump dbname -u root -p ...
45
votes
4answers
59k views

How can I see Time-To-Live (TTL) for a DNS record?

I would like to see the Time-To-Live (TTL) value for a CNAME record. I have access to dig (on Apple Mac OS X), which gives me an answer like this: % dig host.example.gov <*SNIP*> ;; ANSWER ...
11
votes
7answers
72k views

Problem adding Windows 7 64-bit print drivers to a 32-bit Windows 2003 print server

I have installed the final RTM version of Windows 7 Professional 64-bit on a test system before we begin the rollout in our company. I'm having problems connecting to several HP printers that we have ...
8
votes
4answers
52k views

How do I configure proxy settings for LOCAL SYSTEM?

If I edit Proxy Settings through the Control Panel, the settings are stored in HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyEnable and ...\ProxyServer. These ...
31
votes
2answers
29k views

_default_ VirtualHost overlap on port 443, the first has precedence

I have two ruby on rails 3 applications running on same server, (ubuntu 10.04), both with SSL. Here is my apache config file: <VirtualHost *:80> ServerName example1.com DocumentRoot ...
50
votes
1answer
55k views

InnoDB: Error: log file ./ib_logfile0 is of different size

I just added the following lines in /etc/mysql/my.cnf after I converted one database to use InnoDB engine. innodb_buffer_pool_size = 2560M innodb_log_file_size = 256M innodb_log_buffer_size = 8M ...
2
votes
7answers
78k views

Why am I getting 'File in use by Another User' and 'Application Sharing Violation' errors when trying to open & and save files?

We're getting this a lot lately. Windows 2008 Server Windows 7 & Vista Client PC's Microsoft Office 2007 When a user tries opening a file on our network drive (word doc, excel spreadsheet, ...
26
votes
8answers
18k views

My server is still vulnerable to heartbleed even after I update OpenSSL

I have an Ubuntu 12.04 server. I have updated the OpenSSL package in order to fix the heartbleed vulnerability. But I am still vulnerable even, even though I have restarted the web server, and even ...
8
votes
9answers
48k views

How can I check whether port 5060 is open in centos?

How can I check whether port 5060 is open in centos? How can I test if my linux has real a real IP address and I set no iptables blocking rules or is there any tools which I can run in my linux so my ...
60
11
votes
6answers
29k views

CentOS 6 + LDAP + NFS. File ownership is stuck on “nobody”

I've been trying to get LDAP authentication and NFS exported home directories on CentOS 6 working for a few days now. I've gotten to the point that I can now login to the client machine using the ...
53
votes
5answers
59k views

Clean way to write complex multi-line string to a variable

I need to write some complex xml to a variable inside a bash script. The xml needs to be readable inside the bash script as this is where the xml fragment will live, it's not being read from another ...
53
14
votes
3answers
46k views

View Shutdown Event Tracker logs under Windows Server 2008 R2

I'm trying to view the Shutdown Event Tracker logs in the Event Viewer, on windows server 2008 r8, but I can't find the messages that I supplied when previously restart the server. Where in the Event ...
47
votes
1answer
46k views

How do I add Access-Control-Allow-Origin in NGINX?

How do I set the Access-Control-Allow-Origin header so I can use web-fonts from my subdomain on my main domain? Notes: You'll find examples of this and other headers for most HTTP servers in the ...
56
1
vote
9answers
80k views

Can ping Exchange server, can't connect Outlook to it

I can ping the Exchange server here at work, but Outlook doesn't connect to it. I've verified the server is indeed the Exchange server and I've tried using the IP instead of the server name. I am also ...
4
votes
8answers
107k views

How do I remove Windows Update uninstall files on Windows Server 2008?

I'm running Windows Server 2008 Standard running in VMware. It has 2 disks: system disk: 16 GB data disk: 500 MB I installed Visual Studio 2008 SP1 + MSDN and some small tools and ...
18
votes
3answers
66k views

“Possible SYN flooding” in log despite low number of SYN_RECV connections

Recently we had an apache server which was responding very slowly due to SYN flooding. The workaround for this was to enable tcp_syncookies (net.ipv4.tcp_syncookies=1 in /etc/sysctl.conf). I posted a ...
4
votes
6answers
32k views

SQL - an error occurred during the pre-login handshake

Until yesterday evening, I was able to connect to my server from my local machine. Now, I get the following error: A connection was successfully established with the server, but then an error ...
10
votes
10answers
56k views

Network Printers Offline (but not really)

I have two Ricoh printers/copiers setup for IP printing in the office. Before this week there were no problems printing to them. Now a handful of them (All running Vista, not sure if it is every Vista ...
48
votes
3answers
54k views

How to delete Instances in Amazon EC2 ? Change Pair Key?

How to remove Instances ? I test some Instances and now I terminate it. So, I want to remove it. I can't find delete or remove action. I just found terminate. How to change the pair key ? I don't ...
5
votes
4answers
19k views

SSH issues: Read from socket failed: Connection reset by peer

I compiled OpenSSH_6.6p1 on one of our server. I am able login via SSH to the upgraded server. But I am not able to connect to other servers running OpenSSH_6.6p1 or OpenSSH_5.8 from this. While ...
9
votes
2answers
29k views

When an Excel file is locked on a network share, how does it know who locked the file?

We are using Excel 2010 and sometimes users are working from a network share. When a user on the network opens the file in Excel, the file is locked for editing - this is the expected behavior. When ...
22
votes
9answers
48k views

Windows server last reboot time

How can I find a Windows server's last reboot time, apart from 'net statistics server/workstation'?
53
14
votes
5answers
36k views

Dump a linux process's memory to file

Is it possible to dump the current memory allocated for a process (by PID) to a file? Or read it somehow?
10
votes
4answers
40k views

How to save and exit crontab -e?

How to save and exit crontab -e? i tried every method listed here and none works, i have a centos 5, vi comes by default with yum and i installed nano Solved just changed the default editor export ...
55
votes
11answers
11k 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. ...
33
votes
8answers
53k views

OpenVPN vs. IPSec - Pros and Cons, what to use?

Interestingly I have not found any good search results when searching for "OpenVPN vs IPSec". So here my question: I need to setup a private LAN over an untrusted network. And as far as I know, both ...
23
votes
7answers
67k views

Are there any free NFS clients for Windows 7?

I have Windows 7 Professional, but the NFS Client for Windows is only included in the Enterprise and Ultimate editions. I would like to connect some Windows machines to our NFS server so I can drop ...
11
votes
4answers
69k views

Where are my Tomcat Logs?

I installed Tomcat6 on a Ubuntu 9.04 server using apt-get install tomcat6. I uploaded a WAR using the manager interface and tried to start the application but get a pretty generic error on the Web ...
36
votes
3answers
49k views

How can I connect to a Windows server using a Command Line Interface? (CLI)

Especially with the option to install Server Core in Server 2008 and above, connecting to Windows servers over a CLI is increasingly useful ability, if not one that's very widespread amongst Windows ...
63
votes
9answers
71k views

Dealing with HTTP w00tw00t attacks

I have a server with apache and I recently installed mod_security2 because I get attacked a lot by this: My apache version is apache v2.2.3 and I use mod_security2.c This were the entries from the ...
23
votes
8answers
52k views

how to find out mac addresses of all machines on network

Is there some easy way to find out mac address of all machines on my network rather than doing an SSH into each and ifconfig | grep HWaddr if there are 300 machines on network I really need some easy ...
10
votes
5answers
16k views

Set gitlab external web port number

How do I change gitlab's default port 80 to a custom port number? There are two approaches I've tried: Set the port in /etc/gitlab/gitlab.rb external_port "8888" Then run reconfigure: ...
31
18
votes
7answers
12k views

RAID-5: Two disks failed simultaneously?

We have a Dell PowerEdge T410 server running CentOS, with a RAID-5 array containing 5 Seagate Barracuda 3 TB SATA disks. Yesterday the system crashed (I don't know how exactly and I don't have any ...
4
votes
2answers
54k views

How do I mount a “GPT Protective Partition” in Windows XP?

I formatted an external USB harddrive while it was connected to a 32-bit Windows 2003 Server Std. edition server. After loading it up with files, I moved it to my Windows XP SP3 where it didn't show ...
41
votes
1answer
54k views

sudoers: how to disable requiretty per user

I don't want to uncomment the line in /etc/sudoers: Defaults requiretty Instead, I only want a certain user not to require a tty. How can this be done?
49
4
votes
1answer
52k views

TCP/IP ports necessary for CIFS/SMB operation

If I want to allow Windows networked drives between two firewalled computers, do I need to open ports 137-139, or is port 445 sufficient? I have to submit a form and get approval to open firewall ...
3
votes
7answers
39k views

RDP exits immediately after connecting to Windows Server 2008 R2

Background: I recently got a Windows cloud VPS server. I don't have much experience with server admin (I'm a programmer), and what little I do have is with linux servers. Ever since getting the ...
20
votes
3answers
35k views

How do I upgrade to the latest PHP version in CentOS with yum?

I found some blog posts about this, but it's rather lack of descriptions on possible side effects. I could really use some detailed on these steps: How to add a repo that provides PHP 5.4 into yum ...
9
votes
3answers
52k views

How do I know if IP Multicasting is enabled on my network?

Is there a way to know if the Red Hat Linux Servers on my network have IP Multicasting enabled? The output that I get by running the cat /proc/net/igmp command is the following Idx Device : Count ...
6
votes
4answers
34k views

w1228 romb batt < 24h

I just got this message on the front panel of one of our servers, a Dell PowerEdge 2900. I believe this means that the RAID controller card battery is nearly dead. The question that I have is what ...