• Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

Urgent help needed

Joined
Nov 1, 2008
Messages
4,213 (0.75/day)
Location
Vietnam
System Name Gaming System / HTPC-Server
Processor i7 8700K (@4.8 Ghz All-Core) / R7 5900X
Motherboard Z370 Aorus Ultra Gaming / MSI B450 Mortar Max
Cooling CM ML360 / CM ML240L
Memory 16Gb Hynix @3200 MHz / 16Gb Hynix @3000Mhz
Video Card(s) Zotac 3080 / Colorful 1060
Storage 750G MX300 + 2x500G NVMe / 40Tb Reds + 1Tb WD Blue NVMe
Display(s) LG 27GN800-B 27'' 2K 144Hz / Sony TV
Case Xigmatek Aquarius Plus / Corsair Air 240
Audio Device(s) On Board Realtek
Power Supply Super Flower Leadex III Gold 750W / Andyson TX-700 Platinum
Mouse Logitech G502 Hero / K400+
Keyboard Wooting Two / K400+
Software Windows 10 x64
Benchmark Scores Cinebench R15 = 1542 3D Mark Timespy = 9758
Hi guys,

I'm in a bit of a pickle. I went into a friends office to help him sort out a couple of slow computers today and I just got a text that his whole network is down.

His office is a department in a hotel which has a central network system. And I have no idea how it's set up and no experience past SoHo networking.

I initially unplugged a network cable from a desktop and put it into my laptop so I could access the internet. Everything worked fine. However, when I put it back into the desktop, the card only intermittently picked up a signal, though it kept working when I re-plugged it back in to my laptop.

Anyway, I figure his problem is his on an old core 2 solo proc with 1gb of ram and go about upgrading that computer. His laptop is ok, but Skype is slow as he's on shared WiFi which is really slow. So, i figure I can hook him up with WiFi through the office by setting up a cheap DD-WRT repeater. I try to hook the cable up to the computer first, no signal, then laptop, no signal, router no signal.

So I give up on that and continue upgrading the old core solo (to a E7600). I also try pulling a cable from another socket into the router/repeater, but there's no signal from that either.

I tell the girls in the office that they need to contact the IT department to get the network sorted, assuming it's just those 2 connections. (I checked the cables and hardware and all is fine on that end).

Before I leave, one other computer is also not connected to the network, one that I didn't touch, but figured that the IT dept can sort that too.

I just got a message that all the computers are now not able to connect to the network!
I'm wondering if I caused this. Is there any security that would cause a whole office to go down when someone tries to plug in unrecognized/unauthorized devices?

Everything I used is virus free and clean, so my computers would not have been trying to attack the network. I figured that the worst that could happen would be that a device is just denied access. Not causing the whole office to go down!
 
Last edited:
Joined
May 13, 2010
Messages
5,632 (1.11/day)
System Name RemixedBeast-NX
Processor Intel Xeon E5-2690 @ 2.9Ghz (8C/16T)
Motherboard Dell Inc. 08HPGT (CPU 1)
Cooling Dell Standard
Memory 24GB ECC
Video Card(s) Gigabyte Nvidia RTX2060 6GB
Storage 2TB Samsung 860 EVO SSD//2TB WD Black HDD
Display(s) Samsung SyncMaster P2350 23in @ 1920x1080 + Dell E2013H 20 in @1600x900
Case Dell Precision T3600 Chassis
Audio Device(s) Beyerdynamic DT770 Pro 80 // Fiio E7 Amp/DAC
Power Supply 630w Dell T3600 PSU
Mouse Logitech G700s/G502
Keyboard Logitech K740
Software Linux Mint 20
Benchmark Scores Network: APs: Cisco Meraki MR32, Ubiquiti Unifi AP-AC-LR and Lite Router/Sw:Meraki MX64 MS220-8P
Could you please tell us the mfr of the network hardware?
 
Joined
Apr 3, 2012
Messages
4,355 (0.99/day)
Location
St. Paul, MN
System Name Bay2- Lowerbay/ HP 3770/T3500-2+T3500-3+T3500-4/ Opti-Con/Orange/White/Grey
Processor i3 2120's/ i7 3770/ x5670's/ i5 2400/Ryzen 2700/Ryzen 2700/R7 3700x
Motherboard HP UltraSlim's/ HP mid size/ Dell T3500 workstation's/ Dell 390/B450 AorusM/B450 AorusM/B550 AorusM
Cooling All stock coolers/Grey has an H-60
Memory 2GB/ 4GB/ 12 GB 3 chan/ 4GB sammy/T-Force 16GB 3200/XPG 16GB 3000/Ballistic 3600 16GB
Video Card(s) HD2000's/ HD 2000/ 1 MSI GT710,2x MSI R7 240's/ HD4000/ Red Dragon 580/Sapphire 580/Sapphire 580
Storage ?HDD's/ 500 GB-er's/ 500 GB/2.5 Samsung 500GB HDD+WD Black 1TB/ WD Black 500GB M.2/Corsair MP600 M.2
Display(s) 1920x1080/ ViewSonic VX24568 between the rest/1080p TV-Grey
Case HP 8200 UltraSlim's/ HP 8200 mid tower/Dell T3500's/ Dell 390/SilverStone Kublai KL06/NZXT H510 W x2
Audio Device(s) Sonic Master/ onboard's/ Beeper's!
Power Supply 19.5 volt bricks/ Dell PSU/ 525W sumptin/ same/Seasonic 750 80+Gold/EVGA 500 80+/Antec 650 80+Gold
Mouse cheap GigaWire930, CMStorm Havoc + Logitech M510 wireless/iGear usb x2/MX 900 wireless kit 4 Grey
Keyboard Dynex, 2 no name, SYX and a Logitech. All full sized and USB. MX900 kit for Grey
Software Mint 18 Sylvia/ Opti-Con Mint KDE/ T3500's on Kubuntu/HP 3770 is Win 10/Win 10 Pro/Win 10 Pro/Win10
Benchmark Scores World Community Grid is my benchmark!!
Hi guys,

I'm in a bit of a pickle. I went into a friends office to help him sort out a couple of slow computers today and I just got a text that his whole network is down.

His office is a department in a hotel which has a central network system. And I have no idea how it's set up and no experience past SoHo networking.

I initially unplugged a network cable from a desktop and put it into my laptop so I could access the internet. Everything worked fine. However, when I put it back into the desktop, the card only intermittently picked up a signal, though it kept working when I re-plugged it back in to my laptop.

Anyway, I figure his problem is his on an old core 2 solo proc with 1gb of ram and go about upgrading that computer. His laptop is ok, but Skype is slow as he's on shared WiFi which is really slow. So, i figure I can hook him up with WiFi through the office by setting up a cheap DD-WRT repeater. I try to hook the cable up to the computer first, no signal, then laptop, no signal, router no signal.

So I give up on that and continue upgrading the old core solo (to a E7600). I also try pulling a cable from another socket into the router/repeater, but there's no signal from that either.

I tell the girls in the office that they need to contact the IT department to get the network sorted, assuming it's just those 2 connections. (I checked the cables and hardware and all is fine on that end).

Before I leave, one other computer is also not connected to the network, one that I didn't touch, but figured that the IT dept can sort that too.

I just got a message that all the computers are now not able to connect to the network!
I'm wondering if I caused this. Is there any security that would cause a whole office to go down when someone tries to plug in unrecognized/unauthorized devices?

Everything I used is virus free and clean, so my computers would not have been trying to attack the network. I figured that the worst that could happen would be that a device is just denied access. Not causing the whole office to go down!
OOPS! Now you done it!! :D
 
Joined
Mar 10, 2010
Messages
11,878 (2.31/day)
Location
Manchester uk
System Name RyzenGtEvo/ Asus strix scar II
Processor Amd R5 5900X/ Intel 8750H
Motherboard Crosshair hero8 impact/Asus
Cooling 360EK extreme rad+ 360$EK slim all push, cpu ek suprim Gpu full cover all EK
Memory Corsair Vengeance Rgb pro 3600cas14 16Gb in four sticks./16Gb/16GB
Video Card(s) Powercolour RX7900XT Reference/Rtx 2060
Storage Silicon power 2TB nvme/8Tb external/1Tb samsung Evo nvme 2Tb sata ssd/1Tb nvme
Display(s) Samsung UAE28"850R 4k freesync.dell shiter
Case Lianli 011 dynamic/strix scar2
Audio Device(s) Xfi creative 7.1 on board ,Yamaha dts av setup, corsair void pro headset
Power Supply corsair 1200Hxi/Asus stock
Mouse Roccat Kova/ Logitech G wireless
Keyboard Roccat Aimo 120
VR HMD Oculus rift
Software Win 10 Pro
Benchmark Scores 8726 vega 3dmark timespy/ laptop Timespy 6506
Scarcely anything is virus free these days but it does all seam odd , , sounds more like a ip config mass cockup to me but unfortunately I am no network expert if you had touched all the computers that might tell us something.
 
Joined
May 13, 2010
Messages
5,632 (1.11/day)
System Name RemixedBeast-NX
Processor Intel Xeon E5-2690 @ 2.9Ghz (8C/16T)
Motherboard Dell Inc. 08HPGT (CPU 1)
Cooling Dell Standard
Memory 24GB ECC
Video Card(s) Gigabyte Nvidia RTX2060 6GB
Storage 2TB Samsung 860 EVO SSD//2TB WD Black HDD
Display(s) Samsung SyncMaster P2350 23in @ 1920x1080 + Dell E2013H 20 in @1600x900
Case Dell Precision T3600 Chassis
Audio Device(s) Beyerdynamic DT770 Pro 80 // Fiio E7 Amp/DAC
Power Supply 630w Dell T3600 PSU
Mouse Logitech G700s/G502
Keyboard Logitech K740
Software Linux Mint 20
Benchmark Scores Network: APs: Cisco Meraki MR32, Ubiquiti Unifi AP-AC-LR and Lite Router/Sw:Meraki MX64 MS220-8P
The DDWRT router could have triggered as a "Rogue AP" and the APs freaked out. That's why knowing the manufacturer of the networking hardware is important for us to determine how they are supposed to react to this event happening.
 

95Viper

Super Moderator
Staff member
Joined
Oct 12, 2008
Messages
12,645 (2.24/day)
Scarcely anything is virus free these days but it does all seam odd

^This^
You may have a virus/Trojan/anything that does not affect your system(OS) for some reason and it can blow another system(OS) all to heck.
Plus, why were you un-plugging/plugging-in data cables that you know not what they were for.

Tell 'em to reset the router...

You might need a little more information, before the forum members can give you anything but guesses.

Goodluck
 
Joined
Aug 20, 2007
Messages
20,712 (3.41/day)
System Name Pioneer
Processor Ryzen R9 7950X
Motherboard GIGABYTE Aorus Elite X670 AX
Cooling Noctua NH-D15 + A whole lotta Sunon and Corsair Maglev blower fans...
Memory 64GB (4x 16GB) G.Skill Flare X5 @ DDR5-6000 CL30
Video Card(s) XFX RX 7900 XTX Speedster Merc 310
Storage 2x Crucial P5 Plus 2TB PCIe 4.0 NVMe SSDs
Display(s) 55" LG 55" B9 OLED 4K Display
Case Thermaltake Core X31
Audio Device(s) TOSLINK->Schiit Modi MB->Asgard 2 DAC Amp->AKG Pro K712 Headphones or HDMI->B9 OLED
Power Supply FSP Hydro Ti Pro 850W
Mouse Logitech G305 Lightspeed Wireless
Keyboard WASD Code v3 with Cherry Green keyswitches
Software Windows 11 Enterprise (legit), Gentoo Linux x64
I can certify that I am virus free, don't know where this idea that pretty much everything is infected in some form came from... Cookies your antimalware software wants to erase aren't malware, gentlemen.
 

95Viper

Super Moderator
Staff member
Joined
Oct 12, 2008
Messages
12,645 (2.24/day)
I can certify that I am virus free, don't know where this idea that pretty much everything is infected in some form came from... Cookies your antimalware software wants to erase aren't malware, gentlemen.

That's great you are Virus free... Was it your laptop that was plugged into the hotel network?

Nobody said it was cookies. And, nobody said everything is infected.
And, there are viruses/malware out there and they can be tweaked to target certain systems, software, devices, etc.
 
Joined
May 13, 2010
Messages
5,632 (1.11/day)
System Name RemixedBeast-NX
Processor Intel Xeon E5-2690 @ 2.9Ghz (8C/16T)
Motherboard Dell Inc. 08HPGT (CPU 1)
Cooling Dell Standard
Memory 24GB ECC
Video Card(s) Gigabyte Nvidia RTX2060 6GB
Storage 2TB Samsung 860 EVO SSD//2TB WD Black HDD
Display(s) Samsung SyncMaster P2350 23in @ 1920x1080 + Dell E2013H 20 in @1600x900
Case Dell Precision T3600 Chassis
Audio Device(s) Beyerdynamic DT770 Pro 80 // Fiio E7 Amp/DAC
Power Supply 630w Dell T3600 PSU
Mouse Logitech G700s/G502
Keyboard Logitech K740
Software Linux Mint 20
Benchmark Scores Network: APs: Cisco Meraki MR32, Ubiquiti Unifi AP-AC-LR and Lite Router/Sw:Meraki MX64 MS220-8P
The DDWRT router could have triggered as a "Rogue AP" and the APs freaked out. That's why knowing the manufacturer of the networking hardware is important for us to determine how they are supposed to react to this event happening.

Also adding that there could be a laptop with kali/backtrack on the network sending de-authentication attacks, thus disconnecting the connected clients.

The APs (if they are stuff like Meraki/Aruba/etc) should have a log of activity. You would need to check this to get more info. Should be 'rogue AP status' or the like...
 
Joined
Nov 1, 2008
Messages
4,213 (0.75/day)
Location
Vietnam
System Name Gaming System / HTPC-Server
Processor i7 8700K (@4.8 Ghz All-Core) / R7 5900X
Motherboard Z370 Aorus Ultra Gaming / MSI B450 Mortar Max
Cooling CM ML360 / CM ML240L
Memory 16Gb Hynix @3200 MHz / 16Gb Hynix @3000Mhz
Video Card(s) Zotac 3080 / Colorful 1060
Storage 750G MX300 + 2x500G NVMe / 40Tb Reds + 1Tb WD Blue NVMe
Display(s) LG 27GN800-B 27'' 2K 144Hz / Sony TV
Case Xigmatek Aquarius Plus / Corsair Air 240
Audio Device(s) On Board Realtek
Power Supply Super Flower Leadex III Gold 750W / Andyson TX-700 Platinum
Mouse Logitech G502 Hero / K400+
Keyboard Wooting Two / K400+
Software Windows 10 x64
Benchmark Scores Cinebench R15 = 1542 3D Mark Timespy = 9758
I'm going in today to find out what's going on. The connections weren't working (when trying to connect the cables to the pcs) before i tried the AP.

I know the laptop is clean as I use kaspersky + malware bytes. i run periodic rootkit tests and use kaspersky rescue disk to scan on a regular basis.
 
Joined
May 13, 2010
Messages
5,632 (1.11/day)
System Name RemixedBeast-NX
Processor Intel Xeon E5-2690 @ 2.9Ghz (8C/16T)
Motherboard Dell Inc. 08HPGT (CPU 1)
Cooling Dell Standard
Memory 24GB ECC
Video Card(s) Gigabyte Nvidia RTX2060 6GB
Storage 2TB Samsung 860 EVO SSD//2TB WD Black HDD
Display(s) Samsung SyncMaster P2350 23in @ 1920x1080 + Dell E2013H 20 in @1600x900
Case Dell Precision T3600 Chassis
Audio Device(s) Beyerdynamic DT770 Pro 80 // Fiio E7 Amp/DAC
Power Supply 630w Dell T3600 PSU
Mouse Logitech G700s/G502
Keyboard Logitech K740
Software Linux Mint 20
Benchmark Scores Network: APs: Cisco Meraki MR32, Ubiquiti Unifi AP-AC-LR and Lite Router/Sw:Meraki MX64 MS220-8P
I would scan for networks and possibly use tools like wireshark or commview for windows too see if there are any intruders in addition to the above mentioned.
 
Joined
Jan 11, 2013
Messages
1,237 (0.30/day)
Location
California, unfortunately.
System Name Sierra ~ Server
Processor Core i5-11600K ~ Core i3-12100
Motherboard Asus Prime B560M-A AC ~ MSI PRO B760M-P
Cooling CM 212 Black RGB Edition ~ Intel Stock Cooler
Memory 64GB (2x 32GB) DDR4-3600 ~ 32GB (4x 8GB) DDR4-3200
Video Card(s) XFX Radeon RX 6950 XT ~ EVGA GeForce GTX 970
Storage 4TB Samsung 990 Pro with Heatsink NVMe SSD ~ 2TB Kingston NV1 NVMe SSD + 500GB WD Blue SATA SSD
Display(s) 2x Dell S2721QS 4K 60Hz ~ N/A
Case Asus Prime AP201 - Open Frame Chassis
Power Supply Thermaltake GF1 850W ~ Thermaltake Smart 500W
Software Windows 11 Pro ~ Proxmox VE
Benchmark Scores Laptops: Dell Latitude E7270, Dell Latitude 14 Rugged 5420.
Why did we all gravitate towards everything being hacked/infected? I don't see how that is a logical conclusion.

What equipment is being used? If not stock firmware exactly which flavor of aftermarket firmware and versions? Is it a centralized WiFi system like a Cisco/Meraki or Ubiquiti UniFi?

Have you tried new Ethernet cables on things you modified? What happens if you remove your DD-WRT device and reboot whatever is the router? Have you tried obvious steps like rebooting afftected computers?

Do the computers even get IPs? cmd>ipconfig /release and then /renew what happens?
 
Last edited:

95Viper

Super Moderator
Staff member
Joined
Oct 12, 2008
Messages
12,645 (2.24/day)
Why did we all gravitate towards everything being hacked/infected? I don't see how that is a logical conclusion.

He did not give much to go on... Also, a few other things were mentioned.

Plus, why were you un-plugging/plugging-in data cables that you know not what they were for. Tell 'em to reset the router...

It could have been a coincidence, some one else in the office could have knocked it down, the line could have been cut in a construction incident, etc.
Like I said earlier, he will need to give more info or get guesses.

He stated, that, he will be there in the morn, so, maybe, we'll get more info then.

Hard to put a puzzle together without the pieces.

EDIT:

@shovenose: I am not given you a attitude or the like... just saying, we don't know what or how large of a network the are using. Might have been a dedicated network (if it is some chain hotel) and the line he thought was nothing, could had been a dedicated link (he may see no data; however, some equipment there may have been linked securely, or synced up, to it and an admin in the IT dept. may need to re-establish it or it may need to be reset/re-synced. A lot of businesses, governments, etc. use these dedicated specials.
 
Last edited:
Joined
Nov 1, 2008
Messages
4,213 (0.75/day)
Location
Vietnam
System Name Gaming System / HTPC-Server
Processor i7 8700K (@4.8 Ghz All-Core) / R7 5900X
Motherboard Z370 Aorus Ultra Gaming / MSI B450 Mortar Max
Cooling CM ML360 / CM ML240L
Memory 16Gb Hynix @3200 MHz / 16Gb Hynix @3000Mhz
Video Card(s) Zotac 3080 / Colorful 1060
Storage 750G MX300 + 2x500G NVMe / 40Tb Reds + 1Tb WD Blue NVMe
Display(s) LG 27GN800-B 27'' 2K 144Hz / Sony TV
Case Xigmatek Aquarius Plus / Corsair Air 240
Audio Device(s) On Board Realtek
Power Supply Super Flower Leadex III Gold 750W / Andyson TX-700 Platinum
Mouse Logitech G502 Hero / K400+
Keyboard Wooting Two / K400+
Software Windows 10 x64
Benchmark Scores Cinebench R15 = 1542 3D Mark Timespy = 9758
Update: I went back in, and it was only the one connection that was down. His office staff do not have good communication skills.
I got the IT guys on it, and they had disconnected the port because I had plugged in my laptop without having my MAC address registered with them.
Strange security procedure as I was able to connect fully for the first hour!
I doubt that they have enabled the other connection, the one that needs to go into his laptop, I guess I'll find out next time I see him.

He actually wants me to come back in and set up his new office and help purchase 4 new PCs. If I do it, I'll make it clear that I will only install the computers in the office and then communicate with the IT department to make sure they get them set up and ensure they are working.

@shovenose: I am not given you a attitude or the like... just saying, we don't know what or how large of a network the are using. Might have been a dedicated network (if it is some chain hotel) and the line he thought was nothing, could had been a dedicated link (he may see no data; however, some equipment there may have been linked securely, or synced up, to it and an admin in the IT dept. may need to re-establish it or it may need to be reset/re-synced. A lot of businesses, governments, etc. use these dedicated specials.

Yes, It's part of a much larger network, I'm not sure if it's outside the hotel, but they are very security concious for reasons I can't go into. I wish I had known this before going in, or people in the IT department would come down when asked. I went in and was alone there.
 
Last edited:
Joined
Nov 1, 2008
Messages
4,213 (0.75/day)
Location
Vietnam
System Name Gaming System / HTPC-Server
Processor i7 8700K (@4.8 Ghz All-Core) / R7 5900X
Motherboard Z370 Aorus Ultra Gaming / MSI B450 Mortar Max
Cooling CM ML360 / CM ML240L
Memory 16Gb Hynix @3200 MHz / 16Gb Hynix @3000Mhz
Video Card(s) Zotac 3080 / Colorful 1060
Storage 750G MX300 + 2x500G NVMe / 40Tb Reds + 1Tb WD Blue NVMe
Display(s) LG 27GN800-B 27'' 2K 144Hz / Sony TV
Case Xigmatek Aquarius Plus / Corsair Air 240
Audio Device(s) On Board Realtek
Power Supply Super Flower Leadex III Gold 750W / Andyson TX-700 Platinum
Mouse Logitech G502 Hero / K400+
Keyboard Wooting Two / K400+
Software Windows 10 x64
Benchmark Scores Cinebench R15 = 1542 3D Mark Timespy = 9758
I'm just glad I didn't break anything!
 
Top