CaliLivChick

There may already be a thread about this, but with the search function not working....

Why does switching ports on a router make a difference as to how things work?

I have a mini network in my apartment. It consists of two desktops (one Mac, one PC) and a Mac laptop, two printers, and a router. The laptop and the inkjet printer works off my wireless AirPort Express hub. I use either one of the Macs for work, and haven't really had any problems.

Last week, we had a thunderstorm, and that day, I had to restart the network a few times (unplug and replug the power to the cable modem, router, and computers, in that order), but only seemed to have problems when I would connect to the VPN that is needed to get on the servers in the main branch of my company. I would stay connected for awhile, then eventually, my internet connection would just fall away. If I didn't get on the VPN, there were no issues, as I was on the web all weekend, but didn't have problems until I went on the VPN Sunday night.

Our IT guy said to switch the ports that things are in, so I switched the laptop with the PC, and the desktop Mac with the laser printer, and so far, so good. I'm just wondering why that would work like that.

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trache

From the description of the problem, it sounds so far as if the thunderstorm may have damaged your router.

Electricity is a funny thing sometimes, and if it hit your cable modem, travelled down the cable and to your router, it could have damaged only a select port or two.

The port you describe that you switched the laptop with the PC - does the VPN connection and all the network applications you use work on all that physical port with other computers?

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Dilbert1234567

shot in the dark here:
does your router have a specific port that is used for the DMZ? and do you have to use the DMZ for your VPN?

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cyrnel

What device initiates the VPN? The desktop Mac? Is something else now using that device's port successfully?

Odd that only the one connection would send you into the weeds.

What happens if you switch things back? If it keeps working there was probably some ARP table craziness that was cleared by forcing everyone to reintroduce themselves. Still, not that I troubleshoot many VPNs, but that's odd.

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CaliLivChick

Okay, you guys are asking good questions, and I don't really have the answer to all of them (not as much of a techie person), but I'll do the best I can...

I have all of my equipment, including router, cable modem, etc., on power strips with surge protectors... is it still possible for the electricity to get to it?

The VPN is a software thing on my end. I connect to whatever is up at the main office (a VPN box?) that way. I only use the Macs for work (the PC is my bf's), and they both have the software on them. Does that answer that? =)

I don't know what a DMZ is, so I can't answer that at all... =\

After switching, things are still working, and the PC is able to connect... I'm a little hesitant to switch things back... I'm of the mentality that if it isn't broke, don't fix it... but if it will help you guys understand what's happening, and can explain it to me, I'll give it a shot... =)

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maleficent

DMZ is an acronym demilitarized zone, outside of the military it's a small subnetwork that sits between a trusted internal network, such as a corporate private LAN, and an untrusted external network, such as the public Internet.

It's basically a more locked down network...

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xepherys

Actually, a DMZ is a LESS locked down network (from the perspective of your internal network). In corporate environments, public facing servers (like web servers, maybe email, sometimes FTP) are generally put into the DMZ environment so there can be some controls put on them, but so that they can be open to the world without opening up security holes into your corporate LAN/WAN.

Yes, with surge strips electricity can still come through the coax cable. It doesn't sound REALLY likely, but it can happen.

As for ports, well I think cyrnel might have it... some sort of ARP issue or something of that nature, though it's odd that you say the VPN would connect and work for a bit and then drop off. It could've been something temporary at the office, too. If it isn't broken now, don't worry about the "why" of it all. As an IT guy with 12 years of experience I can say assuredly that sometimes you'll just never know for sure.

cyrnel

CaliLivChick, it's odd the VPN connection would cause your net connection to go down. If you ran everything through a VPN router/device it might be less odd. In this case I think "odd" means not enough information or I don't understand the problem.

My comprehension is fertilized this morning (cough) so I'm not quite sure about a couple specifics:Do you mean your entire home network would experience the problems or just the computer using the VPN?

If just the VPN computer, would the other computer then be able to connect to the VPN? Would it then also have the problem?

Edit: Nevermind if it isn't important to you. Sounded like you were curious. As X said, sometimes it's magic (transient or incredibly hard to duplicate). Sometimes it's just not worth the time to figure out. (Of course that judgement may be different between you and a support tech with 5 calls in queue.)

"Have you tried turning the power off and back on again?"
"Call back after you've re-installed Windows and your applications."

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There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195

CaliLivChick

cyrnel - it was the whole network... none of the computers could connect to the internet when it went down, and the other Mac couldn't connect to the VPN either.

I am curious, but if the answer is "sometimes, just because," I'd be okay with that, and will attribute it to the mystery of the internet world that I only partially understand. Like I said, if it's not broke, I'm not inclined to fix it, unless it would help someone else. =)

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cyrnel

And any system would cause the problem once it used the VPN for awhile?

Did the router activity lights seem to be on crack?

I'd like to know more, but then you aren't a customer I have to keep happy by not screwing around. Keep working if it's working. It's quite possible this would require a sniffer or similar to see what's happening. Simplest test I could think of was to put the cables back where they were and try to duplicate it. If it works okay now then I'd assume the router went insane, created some type of storm (heh) by interacting with the VPN code, and resetting the ARP entries "fixed" it. If things go crazy again then restore the working state and record the "do not use" configuration.

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There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195

CaliLivChick

double post

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Don't trust anything that can bleed for a week and not die. Oh wait, that's me... nevermind... you can trust me.

CaliLivChick

well, I only have the two Macs using the VPN, but yes, either one would cause the problem.

The router lights and cable modem lights seemed to be acting normally... that was one of the first things I checked.

I have an update on the situation... I didn't even get things switched back, and the VPN has crashed things again. So my IT guy's next solution is to directly connect my computer to the cable modem, and see how that works.

I've tried an inbetween step, and had my AirPort Express connected to the cable modem, and connect my laptop to the wireless network, but that wasn't happy (my computer was actually lagging so bad it may have been freezing, and I had to take the battery out a couple times in order to restart), so I had to turn off the AirPort connectivity on my laptop, and have the laptop wired directly to the cable modem.

I'll keep things updated... sounds like it could it be the physical router, but if it messes up still, do you think it could be the VPN or my service provider?

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Don't trust anything that can bleed for a week and not die. Oh wait, that's me... nevermind... you can trust me.

cyrnel

I know you'd prefer things to be working but honestly I'm slightly relieved. Some of the magic has gone away.

The fastest test would be to throw a different router in place of your current router. A different brand/model would be best. If the new one has the same problem then you get to complain.

Next fastest (but better if you don't have another router) would be to update firmware (check readme for VPN or relevant changes), reset factory defaults, then configure as needed. See how it behaves. Local routers can play with VPNs though problems are usually more black & white. Like, "it doesn't work".

Yes, the ISP could affect it. Some YokelNet could decide to charge for business accounts and institute traffic shaping to recognize and shut it down. Would depend on the provider and the VPN. Back in the day AT&T YokelCable blocked VPNs for other than business accounts. Bastages. I'm sure some still do this though my few VPN customers have business acounts so I haven't seen it in many moons.

That might not be a bad idea. Check your ISP's terms for anything having to do with VPN's. It would be a coincidence that some policy kicked in right after your power outage, but troubleshooting is filled with coincidence.

__________________
There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195