Re: [CentOS] Which is better? Microsoft Exchange 2016 or Linux-based SMTP Servers?
On Sat, 21 Jul 2018 20:41:40 -0700 Keith Keller wrote: > On 2018-07-22, Valeri Galtsev wrote: > > > > And on top of all: MS Windows is the only systems I know of whose > > vendor tells you, it is not safe to run without 3rd party software > > (antivirus). > > AFAIK (my son runs Windows, to my shame) Windows now comes bundled > with antivirus software. I have no idea if it actually works or not. Yes, isn't it blatant? MS makes defective systems that attract malicious software (viruses) then claims its anti-virus SW is an extra added attraction. No doubt they monetize it somehow.Too baroque for me. The apt cache description of xbill (qv) is just right: "Ever get the feeling that nothing is going right? You're a sysadmin, and someone's trying to destroy your computers. The little people running around the screen are trying to infect your computers with Wingdows [TM], a virus cleverly designed to resemble a popular operating system. Your objective is to click the mouse on them, ending their potential threat. If one of the people reaches a computer, it will attempt to replace your operating system with the virus it carries. It will then attempt to run off the screen with your vital software." Dave > > --keith > ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Which is better? Microsoft Exchange 2016 or Linux-based SMTP Servers?
On 2018-07-21, Michael Schumacher wrote: > folks, didn't anybody check the name of this guy? > > Turritopsis Dohrnii Teo En Ming > drops a bomb with provocative questions every now and then and NEVER > ever responds to his own bullshit. He is just a troll! This is why I asked him why he multiposted to different lists: I saw the same allegation in the Ubuntu group. (Multiposting itself is one minor sign of trolling.) FWIW he did respond to a small handful of messages in this thread. --keith -- kkel...@wombat.san-francisco.ca.us ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Which is better? Microsoft Exchange 2016 or Linux-based SMTP Servers?
On 2018-07-22, Valeri Galtsev wrote: > > And on top of all: MS Windows is the only systems I know of whose vendor > tells you, it is not safe to run without 3rd party software (antivirus). AFAIK (my son runs Windows, to my shame) Windows now comes bundled with antivirus software. I have no idea if it actually works or not. --keith -- kkel...@wombat.san-francisco.ca.us ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Which is better? Microsoft Exchange 2016 or Linux-based SMTP Servers?
On Wed, July 18, 2018 11:42 am, Kenneth Porter wrote: > On 7/18/2018 9:03 AM, mark wrote: >> Based on experience at a number of jobs, Exchange may appear to be easy >> to >> configure, but as soon as you get past the utterly basic configuration, >> when management or other departments want more, it then becomes a major >> headache. > > I like to say that Windows is easier to install and initially configure, > but Linux is much easier to FIX. Things will always go wrong. > Closed-source Windows software hides everything and its GUI often lies > about the true state of what's going on under the hood. Open-source > software can be cracked open and I can dig down to root cause of any > problems. Check out the free support forums at Microsoft. It's pretty > hopeless. Responses to problems with open source software are generally > much more informative. Open source advocates love to show off how they > can fix problems. Closed source engineers aren't allowed to share > solutions with the public. If you really want support, you're going to > have to pay for it. So pay for the product, pay for the support, and nag > them like you own them. Or go with open source and pay a consultant. (Or > a hungry college student.) And on top of all: MS Windows is the only systems I know of whose vendor tells you, it is not safe to run without 3rd party software (antivirus). Antivirus itself is fundamentally flawed idea: you can not enumerate bad. You can enumerate good and prohibit everything else. So, antivirus is like thinking backwards. (But given long record of MS in building poorly architectured system, doing antivirus is sort of job security ;-) Valeri Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] bad text under KDE and C7
> > I don't necessarily mean the video - kernel panics are rarely to do > > with something that far removed from the CPU. I mean test the hardware > > of your computer. > > I'll do the testing suggested. The machine is rather old. > HP Compaq dc5800 sff (small form factor) > I would not be surprised if the kernel > just did not like my motherboard any more. It is very rare that old motherboards (or rather chipsets) stop being supported - I have CentOS 7 running on 10, 15 yr old kit. You get a lot more problems with new motherboards than you get with old ones. > > Even after I figure out the kermal panics, > the video will still be an issue. They may well be linked. > > > First, check the memory - MemTest86+ is the tool most people use for > > this. Run it on your system and it will highlight memory problems. It > > can be found at www.memtest.org - the precompiled versions are tiny and > > will fit on a floppy (or memory stick or CD). > > > > If that doesn't detect anything try running a hardware diagnostic - > > there's a load on the UBCD (www.ultimatebootcd.com) or Hiren's BootCD ( > > www.hiren.info). You might want to download one of those anyway as > > they both contain MemTest86+. > > > > None of this needs you to open the case. > > That is good. > > My suspicion is that this is a repeat of what sent me to Centos from Fedora. > (Yes I know the relationship). > I'm told I couldn't install Fedora on a machine because a > kernel bug affected precisely one kind of motherboard, mine. > I'm also told the bug was supposedly fixed, > but I was never able to run any later Fedora on that machine. You never mentioned that you had previously had issues with Fedora on the machine - not even when I suggested you run a Live version of Fedora to provide different drivers. Not even when you got kernel panics when booting the live Fedora did you mention this was a known issue. P. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS 7 + MATE : Folder contents not refreshed in file manager
On 2018-07-20, Nicolas Kovacs wrote: > Le 13/07/2018 à 21:57, Liam O'Toole a écrit : >> What do you see in /proc/sys/fs/inotify/max_user_watches? If you >> increase the value, does the problem persist? > > I investigated this, and indeed, it solved my problem. > > I wrote a little blog article to summarize my findings and put you in > the Thank You notes. > > https://blog.microlinux.fr/inotify/ > > Cheers, > > Niki > Je vous en prie. :) ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Which is better? Microsoft Exchange 2016 or Linux-based SMTP Servers?
folks, didn't anybody check the name of this guy? Turritopsis Dohrnii Teo En Ming drops a bomb with provocative questions every now and then and NEVER ever responds to his own bullshit. He is just a troll! Michael ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Which is better? Microsoft Exchange 2016 or Linux-based SMTP Servers?
On 7/18/2018 9:03 AM, mark wrote: Based on experience at a number of jobs, Exchange may appear to be easy to configure, but as soon as you get past the utterly basic configuration, when management or other departments want more, it then becomes a major headache. I like to say that Windows is easier to install and initially configure, but Linux is much easier to FIX. Things will always go wrong. Closed-source Windows software hides everything and its GUI often lies about the true state of what's going on under the hood. Open-source software can be cracked open and I can dig down to root cause of any problems. Check out the free support forums at Microsoft. It's pretty hopeless. Responses to problems with open source software are generally much more informative. Open source advocates love to show off how they can fix problems. Closed source engineers aren't allowed to share solutions with the public. If you really want support, you're going to have to pay for it. So pay for the product, pay for the support, and nag them like you own them. Or go with open source and pay a consultant. (Or a hungry college student.) ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] odd popups
No image found. This may be due to ABRT. Expand the details at the bottom of the pop-up and if the Vendor is "The ABRT Team", then the pop-up is benign. You can read problems you have encountered, but if a daemon or any other user hits a problem you do not have the authority to look at their processes. To further check this, go to Applications>System Tools>Automatic Bug Reporting Tool. You can look at the "My" tab, but looking at the "System" tab (for example) will trigger the pop-up. Enter the root password (if you know it) and you will see a list of System's problems. On 21/07/18 01:41, Fred Smith wrote: > Occasionally and without any action on my part, I get a popup > saying I need to authenticate in order to read others' actions. > I have no clue what this is for, so I always reject them. > Anyone got a clue? > > Image attached. > signature.asc Description: OpenPGP digital signature ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] bad text under KDE and C7
On Sat, 21 Jul 2018, Pete Biggs wrote: On Fri, 2018-07-20 at 10:10 -0500, Michael Hennebry wrote: On Tue, 17 Jul 2018, Pete Biggs wrote: Check your hardware - all these things might well be symptomatic of an hardware issue. I'm not at all sure how. If it means opening the case, hardware issues are likely to occur. Is there a way to tell whether the video player is even using video acceleration? I don't necessarily mean the video - kernel panics are rarely to do with something that far removed from the CPU. I mean test the hardware of your computer. I'll do the testing suggested. The machine is rather old. HP Compaq dc5800 sff (small form factor) I would not be surprised if the kernel just did not like my motherboard any more. Even after I figure out the kermal panics, the video will still be an issue. First, check the memory - MemTest86+ is the tool most people use for this. Run it on your system and it will highlight memory problems. It can be found at www.memtest.org - the precompiled versions are tiny and will fit on a floppy (or memory stick or CD). If that doesn't detect anything try running a hardware diagnostic - there's a load on the UBCD (www.ultimatebootcd.com) or Hiren's BootCD ( www.hiren.info). You might want to download one of those anyway as they both contain MemTest86+. None of this needs you to open the case. That is good. My suspicion is that this is a repeat of what sent me to Centos from Fedora. (Yes I know the relationship). I'm told I couldn't install Fedora on a machine because a kernel bug affected precisely one kind of motherboard, mine. I'm also told the bug was supposedly fixed, but I was never able to run any later Fedora on that machine. -- Michael henne...@web.cs.ndsu.nodak.edu "Sorry but your password must contain an uppercase letter, a number, a haiku, a gang sign, a heiroglyph, and the blood of a virgin." -- someeecards ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] database node / possible SYN flooding on port 3306
On 07/21/2018 03:48 AM, Leon Fauster via CentOS wrote:
>> Am 20.07.2018 um 18:52 schrieb Nataraj :
>>
>> On 07/20/2018 03:56 AM, Leon Fauster via CentOS wrote:
>>> Hi folks,
>>>
>>> I have here a database node running
>>>
>>> # rpm -qa | grep mysql-server
>>> mysql55-mysql-server-5.5.52-1.el6.x86_64
>>>
>>> on
>>>
>>> # virt-what
>>> vmware
>>>
>>>
>>> that seems to have a connection problem:
>>>
>>> # dmesg |grep SYN |tail -5
>>> possible SYN flooding on port 3306. Sending cookies.
>>> possible SYN flooding on port 3306. Sending cookies.
>>> possible SYN flooding on port 3306. Sending cookies.
>>> possible SYN flooding on port 3306. Sending cookies.
>>> possible SYN flooding on port 3306. Sending cookies.
>>>
>>>
>>> I adapted already following:
>>>
>>> # sysctl -a |grep -E 'maxconn|syn_backlog'
>>> net.core.somaxconn = 2048
>>> net.ipv4.tcp_max_syn_backlog = 2048
>>>
>>>
>>> but ListenOverflows and ListenDrops values are still high
>>>
>>> # cat /proc/net/netstat | awk '{print $21 "-" $22 }'
>>> ListenOverflows-ListenDrops
>>> 13568-13568
>>>
>>> any suggestion?
>> Use tools like tcpdump/wireshark and further examination of logfiles to
>> determine where your attack is coming from, i.e. single IP address or
>> multiple ip addresses (BOT attack).
>>
>> If attack is impairing your Internet service, contact your ISP. Most
>> decent ISP's should deal with this situation for you.disabled
>>
>> If attack is not impairing your service and you choose to deal with it
>> yourself, then, if from a fixed IP address block that IP from your
>> firewall if you have one, otherwise, use IPtables on the server. If
>> your having bot attacks, or blocking attack causes source IP address to
>> be changed, then look at fail2ban. Basically you want to configure
>> fail2ban to limit the number of requests per unit of time and block IPs
>> that exceed that. Also, consider weather your database needs to be
>> publicly accessible from the Internet.
>
> Actually the database node is a backend system in a private network, so "all"
> traffic is legitimate. The main traffic comes from the web node (cms/php).
> Resources
> of the db node seems all to be okay (cpu/mem/load). So i do not see any
> bottleneck ...
>
> --
> LF
> https://www.google.com/search?client=ubuntu=fs=mysql+possible+syn+flooding=utf-8=utf-8
>
>
> ___
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I would still use tcpdump and/or wireshark to find out more what is
going on and if all the incoming connections seem correct, you may have
to tune some parameters to allow a greater number of connections. Also,
if you have iptables connection tracking turned on, this might need to
be bypassed for connection on your database port. Connection tracking
does not always work well for large numbers of connections. But check
to see weather one or more clients are somehow failing to connect and
retrying the connection at a high rate for some reason.
Also Try
https://www.google.com/search?client=ubuntu=fs=mysql+possible+syn+flooding=utf-8=utf-8
and maybe this:
https://help.marklogic.com/Knowledgebase/Article/View/182/0/possible-syn-flooding-messages-in-system-logs
Nataraj
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Re: [CentOS] bad text under KDE and C7
Le 10/07/2018 à 08:26, Michael Hennebry a écrit : > KDE is not doing so well either. Here's what KDE on CentOS looks like here: https://i1.wp.com/blog.microlinux.fr/wp-content/uploads/2017/01/centos-7-kde.png?ssl=1 Cheers, Niki -- Microlinux - Solutions informatiques durables 7, place de l'église - 30730 Montpezat Site : https://www.microlinux.fr Blog : https://blog.microlinux.fr Mail : i...@microlinux.fr Tél. : 04 66 63 10 32 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] bad text under KDE and C7
On Fri, 2018-07-20 at 10:10 -0500, Michael Hennebry wrote: > On Tue, 17 Jul 2018, Pete Biggs wrote: > > > Check your hardware - all these things might well be symptomatic of an > > hardware issue. > > I'm not at all sure how. > If it means opening the case, > hardware issues are likely to occur. > > Is there a way to tell whether the video > player is even using video acceleration? > I don't necessarily mean the video - kernel panics are rarely to do with something that far removed from the CPU. I mean test the hardware of your computer. First, check the memory - MemTest86+ is the tool most people use for this. Run it on your system and it will highlight memory problems. It can be found at www.memtest.org - the precompiled versions are tiny and will fit on a floppy (or memory stick or CD). If that doesn't detect anything try running a hardware diagnostic - there's a load on the UBCD (www.ultimatebootcd.com) or Hiren's BootCD ( www.hiren.info). You might want to download one of those anyway as they both contain MemTest86+. None of this needs you to open the case. P. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS-virt] Network Problem KVM
Hello List, CentOS 7.5 I have a question about a KVM problem (??) with my Servers, I hope any have a answer. ;-) My situation is, I have three server two identical motherboards and one 19" Server. The problem is the configuration with the Bridge Interface! On my motherboards I have configured a NIC for bridge, on the 19" Server I have the virbr0 from KVM configured. All Server (motherboards) have a Intel I350 Ethernet Controller on Board, I configured this NIC's with the "igb" driver and in the KVM clients with with the "hostdev" option this two Interfaces are starting always correct. But the "BRIGED" interfaces is the third Interface on all "servers", is starting only sometimes :-(. I have to check all clients after a kernel update for correct networking? The only way to have again correct working clients is to reboot or stop and start the clients sometimes three or four times and again. I have on all "Servers" 4-6 KVM Clients and this is a BIG problem for me! Why is this possible (?), is my configuration broken or is a driver broken or... thanks for a answer and help is possible, -- mit freundlichen Grüssen / best regards, Günther J. Niederwimmer ___ CentOS-virt mailing list CentOS-virt@centos.org https://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS] database node / possible SYN flooding on port 3306
> Am 20.07.2018 um 18:52 schrieb Nataraj :
>
> On 07/20/2018 03:56 AM, Leon Fauster via CentOS wrote:
>> Hi folks,
>>
>> I have here a database node running
>>
>> # rpm -qa | grep mysql-server
>> mysql55-mysql-server-5.5.52-1.el6.x86_64
>>
>> on
>>
>> # virt-what
>> vmware
>>
>>
>> that seems to have a connection problem:
>>
>> # dmesg |grep SYN |tail -5
>> possible SYN flooding on port 3306. Sending cookies.
>> possible SYN flooding on port 3306. Sending cookies.
>> possible SYN flooding on port 3306. Sending cookies.
>> possible SYN flooding on port 3306. Sending cookies.
>> possible SYN flooding on port 3306. Sending cookies.
>>
>>
>> I adapted already following:
>>
>> # sysctl -a |grep -E 'maxconn|syn_backlog'
>> net.core.somaxconn = 2048
>> net.ipv4.tcp_max_syn_backlog = 2048
>>
>>
>> but ListenOverflows and ListenDrops values are still high
>>
>> # cat /proc/net/netstat | awk '{print $21 "-" $22 }'
>> ListenOverflows-ListenDrops
>> 13568-13568
>>
>> any suggestion?
>
> Use tools like tcpdump/wireshark and further examination of logfiles to
> determine where your attack is coming from, i.e. single IP address or
> multiple ip addresses (BOT attack).
>
> If attack is impairing your Internet service, contact your ISP. Most
> decent ISP's should deal with this situation for you.
>
> If attack is not impairing your service and you choose to deal with it
> yourself, then, if from a fixed IP address block that IP from your
> firewall if you have one, otherwise, use IPtables on the server. If
> your having bot attacks, or blocking attack causes source IP address to
> be changed, then look at fail2ban. Basically you want to configure
> fail2ban to limit the number of requests per unit of time and block IPs
> that exceed that. Also, consider weather your database needs to be
> publicly accessible from the Internet.
Actually the database node is a backend system in a private network, so "all"
traffic is legitimate. The main traffic comes from the web node (cms/php).
Resources
of the db node seems all to be okay (cpu/mem/load). So i do not see any
bottleneck ...
--
LF
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