I have some experience with Linux, I used Novell at my old job (IT Director for a school system) and a fan of ubuntu, but I have never laid eyes on CentOS until I landed here. Long story short, the last IT person was mean and left with no notes, no guidance, and a restraining order... so I can't ask him. Best I can tell, this CentOS 5.5 is handling our DHCP... maybe other things, I can't tell. We are starting to have issues, and I realized today that I cannot update it.

I'm looking for advice, suggestions or at the least sympathy. What would you do? Where do I start? Any help and prompting questions much appreciated.

http://monster.com ...

(just kidding)

A restraining order? Wow.

What you need to do is to tell us exactly what each issue is – and what you attempted in order to solve it – and what impediments you encountered. Be as specific as you possibly can. We all will be happy to help you at once.

First, you need to see if you can log on as root, or if the command sudo su (with your own password) gets you to a # prompt. If you can't get that far, let us know. Otherwise it will simply become a matter of identifying each symptom and advising us of it.

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CentOS vs. Ubuntu vs. Any-Linux-Distro = not a whole lot different. You have pretty much the same commands on Ubuntu as you do on CentOS, with some differences that aren't earth-shaking.

If I was you, I'd approach this in an orderly fashion, to let you work through problems and learn the new system as you go. So:

• (Ideal world) Purchase a new server, load the latest version of CentOS on it (7.x), and bring it up on your network, along with your current server. Copy config files over, and configure services. Test after hours, by bringing old server down/unplugging from LAN, and letting your new one assume the address. Repeat steps for each service.
• (Good enough) Get a new hard drive for your existing server along with SATA to USB adapter. Do a fresh load, copy config files over, and configure services. Things go REALLY bad? Swap hard drives back and you're back on the air.

CentOS 5.x is end of life; no updates possible, and not even the possibility of getting up to date without a LOT of work. And no guarantees that the services will work afterwards, since config options may have changed.

Find out what services are running. Run "netstat -an | grep LISTEN" for a list of running network services/ports. Identify what's there by port # (80 for http, 443 for https, etc., etc.) Then it should be a matter of configuring those services by following the instructions for each one. Your old configs should be (mostly) under /etc somewhere, and MAY work..and may not. If they don't, walk through them one at a time, and get things back up. Listen for screams from users, and repair as needed.

Good luck.

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I don't know...personally, I sort of *LIKE* coming in that way. Because I can then build things up correctly and KNOW how they work, rather than having to guess.

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I do have root credentials. So far, the only changes I have made are 1) creating my own user, 2) attempted to disable the former guy's users (He was using a VPN to mess with our stuff after he was relieved of his duties - thus the restraining order/charges filed), and 3) try to update.

Specifically, I'm having slowness issues when everyone turns on their computers all at once... (I have ruled out AP issues) We have mandatory Chromebook time twice each day school wide) and also having an issue where reservations aren't taking on the devices like printers, my workstation, etc.

Since all the help sites I've found are for OS versions beyond what I have, I wanted to update first and foremost.

I have a Dell PowerEdge R710 server that was running PFSense providing DNS and VPN capabilities. That was where the mean guy was getting in. He WAY screwed up our DNS. I switched to using the DNS of the ISP and unplugged that server. Would it be salvageable to do what you're describing? Can you talk me through that process? I did download the iso of the latest CentOS... do I need to do anything special to that old server before I start fresh? I'm bordering on out of my league here.

No. Again, your server is so old it can't be updated, so start fresh. Especially if you think it's been compromised in any way, the safest thing is to format the drive and load fresh.
We are happy to help with specific questions, but an entire step-by-step guide isn't really doable. That's veering into "hire-a-consultant" territory.
If you unplugged the server and things are running...why do you think you NEED that server back to start with? What did it do that you don't have now? If all you're missing is OpenVPN, setting that up on CentOS is fairly easy. You can find many how-to guides on how to install/configure OpenVPN on CentOS. And unless you *NEED* a pretty robust internal DNS solution, I'd suggest looking at setting up DNSMASQ, which is VERY easy to do, and can easily use the upstream DNS servers (like those of Google...I'd avoid ISP DNS servers). That puts you back in business, and you can find MANY how-to guides for installing both.

Loading CentOS? Hardly much different than Ubuntu; put DVD in drive, boot from it, follow instructions on screen. In your case, I'd delete ALL your current partitions and format your drive(s), and then let the installer partition your disks for you (if you're uncomfortable with it...as said, not different from ubuntu in a lot of ways). After reboot, you can probably install dnsmasq and openvpn with something like "yum install dnsmasq" and "yum install openvpn". Again, many easily-found guides can tell you how.

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I think I didn't explain that well. I unplugged a separate server that is now just sitting there available. I was asking if that would be a viable candidate for the freshly installed newer version of CentOS. The one with the very old CentOS is still up and running, just buggy.

Curious though... why do you avoid ISP DNS? For the benefit of the school, I've been told (by the ISP) that it's preferable to use theirs as the content filter lies on their side of things. I did have it as google for a bit, when I was discovering the DNS issues we were having earlier in the school year.

does He have to use CentOS for His Base Distro OS?
the start from new/fresh saving old config files sounds like the best idea. But does He have to use CentOS for His Base Distro OS or can he use some other Linux Distro?

It's going to be easier to stick with Centos if that's what is running now.
We don't know what's running on these systems & there may be specific stuff that is only supported on RHEL ie centos.

@OP:
For your new server, definitely get the latest v7.x - v5 is beyond updating and v6 is getting old. Ref https://access.redhat.com/support/po...pdates/errata/

Do have a chat to mgrs about the possibility of going RHEL & thus getting paid support - you may need it, if only for one machine. The same advice will apply to Centos as well.


DNS: if ISP is supplying school-safe filtering, you should prob stick with that and indeed may be legally obliged to in case kids go somewhere they shouldn't ...

You do really need to talk to the mgrs and find out what restrictions/expectations are in place.

This is very useful http://www.linuxtopia.org/ ; a huge num of manuals/books etc - free to read online, inc RHEL/Centos specific stuff.


Once you get a new 7.x server up, try to match one of the existing ones and come to us with separate qns for each issue.

On the old machine try these
to see services avail/running etc

V7.x has a new syntax, but (atm) the old syntax generally works - it just re-directs to new one.

This is a nice online searchable version of man pages http://linux.die.net/man/

Remember that RHEL/Centos use yum (& rpm) pkg mgr cmds

HTH

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Yes, should work just fine.
Because of ISP redirections and/or snooping. Type in a bad web page address using the Google public DNS and you get a "not found" page. Do it with your ISP and see what happens.

So far, so good. I've gotten the newer CentOS 7.* installed on that "spare" server I had. I'm thinking to do quite a bit of educating before I try to move settings, and was wondering, since I suspect that some things are maybe not configured in the best way possible, I'm considering replicating in the new one rather than importing from the old. Thoughts?

Also, I do have a failsafe.... the ISP can provide DHCP with their equipment, should I completely ruin things. I would lose the ability to make/modify my own reservations, but otherwise, the network would work.