Office LAN nightmares....help! 2

[xedgex]

Let me outline the office network and WAN setup before I explain the problem.

We have 1 DSL modem; netopia -> linksys 4 port router -> 16 port netgear GBe switch -> patch panel -> drops most of which has a 4 port netgear hub I think 10/100

Default Gateway is the linksys router
DNS is our file server

We have been losing access to the internet on and off pretty frequently lately, while this happens our internal access goes offline too. We've talked to the ISP and while they found issues I feel the problem is mainly internal. What I did was hook myself up to the dsl modem directly with another external ip address and run a continuous ping to google as well as a known external IP address. I watched for this to fail at the same time that our internal network would, but it did not. Out internal ping tests to the router or server failed but I was still able to get ourside through a direct ethernet to the modem.

I figure the issue has to be these little 4 port hubs all over the place or the GbE switch or possibly the linksys (brand new). My first step will be replacing one of the 4 port hubs with a GbE one to see if it helps that area of the office, I have noticed that an internal issue when not being able to ping a resource isnt present for everyone at the same time, it varies on which office they are in / which drop they are connected to.

Also, DNS is set to a win2000 server, which does not have Forwarders added, should I add my ISP's dns addresses here?

Another idea I have is to connect one of the troubled PCs directly into the switch and see if its problems surface with the rest of the office or not.

Could some of these hubs be 'looping' the main switch? I need some advise on troubleshooting this, thank you for any input!!

 

[North323]

how many lan computers do you have? are they all in the same subnet? do you have some computers in the back of the linksys as well as the 4 port hub?

 

[xedgex]

about 10 computers total. the linksys internet port goes to netopia, and lan port 1 goes into the 16 port GbE switch. No, any computers on these 4 port hubs come into a single port on the patch panel and then plugged into the 16 port switch.

Here's a thought, what if I have more than 16 tcp/ip devices on the LAN, could the GbE switch be overwhelmed and cause these intermitten problems?

 

[xedgex]

Yes there is only 1 subnet.

 

[brianinms]

I am confused. If you only have 10 computers and you have a 16port switch then why do you have all the hubs? If you are losing connection to the internal server then it would indicate a problem with your 16port switch. I would work to eliminate as many of the 4port hubs as possible.

 

[North323]

i second that thought

 

[jimbopalmer]

I am unaware of any Netopia 'modem' which is not actually a router. What is the model you have?

If you have back to back routers, there is all kinds of internet problems you can have.

http://episteme.arstechnica.com/eve...36/m/735009307831?r=287009507831#287009507831

I tried to remain child-like, all I acheived was childish.

 

[North323]

it would depend on what mode the netopia is in. if its in bridge mode, its just passing traffic

 

[SimonDavies]

Hang on, if you have multiple 4 port hubs that are all failing then the logical thing would be that it's failing at the 16 port Switch. I doubt it's the router as that would only impact Internet based traffic rather than LAN based.

The only other thing that could cause all of these devices to fail at the same time is if you're running power cables alongside the lan cables and you're getting bleed over due to RFI. My gut tells me tho that the 16 port switch would be the first place to look.

You're probably getting along with Root Hints OK but you may be better off putting conditional forwarders in place anyway.

Simon

The real world is not about exam scores, it's about ability.

 

[xedgex]

We we need these stupid 4 port hubs because each large office room only has 1 ethernet drop, some of these room have 2-3 computers.

What should I replace 1st? the 16 port? or try the hubs? Please keep in mind that when we 'fail' internally it doesnt mean everyone at once, I saw some internal pings fail on one pc but not on another in a different office. When we fail it seems that we cant ping the linksys router, hence we cant get out, but WAN is ok if I try to get out over it by bypassing the linksys. It's not hte provider, its definitely internal issue, I just dont know what to start with.

This is a VERY old building, I'm afraid some of the drops could be next to electrical lines which can cause the interference that was mentioned above, I have no idea how to troubleshoot that.

 

[technome]

(Aside from speed/duplex issues causing dropouts, caused by a wire(s) which will not pass CAT certification.)

"This is a VERY old building"
Are all the hub/switch/routing devices on battery backup units. Small hubs/routers generally have minimal power capacitors, and do not handle even small power anomalies well.

........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[edfair]

My first inclination would be to trash the little hubs and replace them with little switches. No telling what kind of network havoc them little active broadcast repeaters might be doing.

And I would set up DNS through the router as a test, although that might make things worse for the duration.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[jimbopalmer]

They may have used hubs (as opposed to switches) so the ethernet would be slower and less failure prone. Auto-negotiation only asks the electronics how fast they can go, not the cabling.

If you replaced the 16 port switch with a managed switch, you could see which lines had errors.

If an 8 port is enough

http://www.newegg.com/Product/Product.aspx?Item=N82E16833316090

22 port

http://www.newegg.com/Product/Product.aspx?Item=N82E16833316091

With decent diagnostics in the core of your network, you could step up to switches at the edge.

http://www.newegg.com/Product/Product.aspx?Item=N82E16833166006

I tried to remain child-like, all I acheived was childish.

 

[xedgex]

The little scattered hubs are not on any sort of UPS or battery backup. I will be replacing the switch with a 10/100 24 port so I have more ports and I match the fast ethernet speed, I don't think there's a single machine that has a gbe NIC anyway. I will also replace one of these hubs with a 5 port switch.

Thank you all for your awesome replies, I truly appreciate it! I'll post feedback tomorrow, hopefully I'm able to narrow it down or resolve the issue completely.

 

[jimbopalmer]

I sure wish I had read the word 'managed' when he considered buying a 24 port switch.

I tried to remain child-like, all I acheived was childish.

 

[xedgex]

boy oh boy....nothing seems to help here.

I swapped the 16 port gbe netgear with a 24 port 10/100 cisco/linksys switch. no help. I eliminated all hubs from the network, no help.

At this point I think the problem is the Linksys DSL router.

Once in a while when the network goes down I get;

PING: transmit failed, error code 1231.

This is on a ping to an internal server as well as the internal router ip address....what does this code mean?

 

[North323]

are this computers having a problem using VISTA? are you using IPV6?

 

[xedgex]

all are XP, I alone use Vista, no ipv6, it may be enabled on a PC somewhere, I'm not sure. Should I look for ipv6 enabled PC's? would that matter?

 

[SimonDavies]

Out of interest how are you assigning the IP addresses? Are you experiencing any issues on the DHCP server? I am wondering if this is down to a lack of IP addresses and lease times instead?

Simon

The real world is not about exam scores, it's about ability.

 

[North323]

IPv6 could potentially be an issue but if they are XP boxes then they do not have that feature enabled. try to upgrade the firmware on your router to the latest and see if IPv6 is somehow enabled on the router, if so, disable.