User Mike B

143 votes

2 answers

461k views

How can I verify if TLS 1.2 is supported on a remote web server from the RHEL/CentOS shell?

asked Oct 21, 2014 at 20:39

121 votes

7 answers

205k views

REJECT vs DROP when using iptables

asked Jul 4, 2010 at 9:49

107 votes

6 answers

118k views

"POSSIBLE BREAK-IN ATTEMPT!" in /var/log/secure — what does this mean?

asked Apr 17, 2011 at 18:17

82 votes

6 answers

118k views

Do SPF Records For Primary Domain apply to subdomains?

asked Oct 19, 2011 at 15:59

30 votes

6 answers

126k views

What causes Scheduled Task error 2147942402?

asked Dec 4, 2013 at 21:17

27 votes

3 answers

97k views

How can I configure netcat (or some other stock linux utility) to listen on a specific port on a secondary IP address?

asked May 31, 2013 at 16:25

23 votes

2 answers

34k views

Are two periods allowed in the local-part of an email address?

asked Jun 5, 2012 at 15:23

21 votes

2 answers

134k views

What is [PSH, ACK] doing during my connection to a global catalog server?

asked Jul 22, 2014 at 17:34

19 votes

2 answers

30k views

Is it OK to have multiple TXT records for a single domain containing different SPF entries?

asked Jan 7, 2014 at 17:51

18 votes

2 answers

65k views

How can I search the info column in Wireshark?

asked Oct 19, 2010 at 22:36

15 votes

6 answers

15k views

How can I easily convert HTML special entities from a standard input stream in Linux?

asked Oct 22, 2012 at 2:21

15 votes

3 answers

17k views

What is the difference between "dnl" and "dnl #" in a sendmail.mc file?

asked Feb 8, 2014 at 5:17

14 votes

3 answers

42k views

What exactly do --limit 1/s and --limit-burst mean in iptables rules?

asked Mar 6, 2013 at 22:09

11 votes

4 answers

28k views

Why is ethtool not showing me all the properties for a NIC?

asked Nov 12, 2012 at 18:27

11 votes

3 answers

22k views

Does the presence of a Content-ID header in an email MIME mean that the attachment must be embedded?

asked Jun 14, 2012 at 21:53

10 votes

2 answers

23k views

What exactly is AVAHI?

asked Aug 28, 2010 at 20:55

9 votes

2 answers

9k views

Can I use an SSH tunnel to access a web server that's listening on a different IP/Port on the same server?

asked Jan 17, 2012 at 18:48

9 votes

4 answers

2k views

When is it appropriate / prudent to use chroot?

asked Dec 23, 2009 at 23:24

9 votes

4 answers

5k views

How can I easily confirm in Linux that two separate directories have the exact same contents?

asked May 18, 2012 at 20:43

9 votes

3 answers

4k views

Why does the "free" command and "dmidecode" show different values for RAM?

asked Oct 29, 2014 at 17:33

7 votes

1 answer

11k views

How can I confirm if my vmxnet driver is installed on my CentOS server?

asked Mar 16, 2015 at 16:05

7 votes

2 answers

2k views

Is there a graceful way to pick up new changes in sendmail?

asked Jun 20, 2015 at 7:55

7 votes

1 answer

4k views

Why is sendmail adding an extra carriage return in headers?

asked Jul 17, 2015 at 17:50

7 votes

2 answers

7k views

How can I decrypt STARTTLS communication over SMTP in a packet capture (if I have the private key)?

asked Aug 11, 2017 at 17:29

7 votes

1 answer

17k views

How can I tell who/what shutdown my CentOS VPS?

asked Nov 23, 2011 at 20:22

6 votes

2 answers

6k views

Is there a way to completely disable outbound opportunistic TLS support in SendMail?

asked Jan 5, 2012 at 0:45

6 votes

1 answer

1k views

Are there certain specific host file entries that Windows 2008 will ignore for security purposes?

asked Jul 13, 2012 at 15:42

6 votes

2 answers

22k views

Is it necessary to manually rebuild a sendmail.cf file or is this done automatically on service restarts?

asked Mar 12, 2013 at 19:16

5 votes

1 answer

18k views

How can I retrieve the LDAP server certificate for Windows 2008 and 2003 global catalog servers?

asked Aug 24, 2012 at 0:46

5 votes

5 answers

31k views

How can I monitor memory usage for a windows-based JVM and trigger an alert if it gets too high?

asked Jul 3, 2012 at 17:48

Stack Exchange Network

225 Questions

How can I verify if TLS 1.2 is supported on a remote web server from the RHEL/CentOS shell?

REJECT vs DROP when using iptables

"POSSIBLE BREAK-IN ATTEMPT!" in /var/log/secure — what does this mean?

Do SPF Records For Primary Domain apply to subdomains?

What causes Scheduled Task error 2147942402?

How can I configure netcat (or some other stock linux utility) to listen on a specific port on a secondary IP address?

Are two periods allowed in the local-part of an email address?

What is [PSH, ACK] doing during my connection to a global catalog server?

Is it OK to have multiple TXT records for a single domain containing different SPF entries?

How can I search the info column in Wireshark?

How can I easily convert HTML special entities from a standard input stream in Linux?

What is the difference between "dnl" and "dnl #" in a sendmail.mc file?

What exactly do --limit 1/s and --limit-burst mean in iptables rules?

Why is ethtool not showing me all the properties for a NIC?

Does the presence of a Content-ID header in an email MIME mean that the attachment must be embedded?

What exactly is AVAHI?

Can I use an SSH tunnel to access a web server that's listening on a different IP/Port on the same server?

When is it appropriate / prudent to use chroot?

How can I easily confirm in Linux that two separate directories have the exact same contents?

Why does the "free" command and "dmidecode" show different values for RAM?

How can I confirm if my vmxnet driver is installed on my CentOS server?

Is there a graceful way to pick up new changes in sendmail?

Why is sendmail adding an extra carriage return in headers?

How can I decrypt STARTTLS communication over SMTP in a packet capture (if I have the private key)?

How can I tell who/what shutdown my CentOS VPS?

Is there a way to completely disable outbound opportunistic TLS support in SendMail?

Are there certain specific host file entries that Windows 2008 will ignore for security purposes?

Is it necessary to manually rebuild a sendmail.cf file or is this done automatically on service restarts?

How can I retrieve the LDAP server certificate for Windows 2008 and 2003 global catalog servers?

How can I monitor memory usage for a windows-based JVM and trigger an alert if it gets too high?