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Professional Discussions => Routing and Switching => Topic started by: KARTHIKEYAN.K on January 21, 2017, 02:15:19 AM

Title: NETWORKING BASICS
Post by: KARTHIKEYAN.K on January 21, 2017, 02:15:19 AM
NETWORKING BASICS
Title: Re: NETWORKING BASICS
Post by: deanwebb on January 21, 2017, 08:58:34 AM
I guess one would start with "always check the temperature and ventilation in the network closet".
Title: Re: NETWORKING BASICS
Post by: that1guy15 on January 21, 2017, 10:04:36 AM
plug both ends of the wire in.
Title: Re: NETWORKING BASICS
Post by: deanwebb on January 21, 2017, 10:16:13 AM
Quote from: that1guy15 on January 21, 2017, 10:04:36 AM
plug both ends of the wire in.
And take notes. When you see this again, look for the wire with both ends plugged in. Maybe it will take you less than the 12 hours it took to solve when it happened to me, 4 years ago... :lol:
Title: Re: NETWORKING BASICS
Post by: icecream-guy on January 22, 2017, 10:12:47 AM
if in doubt - reboot it.

:itcrowd:
Title: Re: NETWORKING BASICS
Post by: Otanx on January 23, 2017, 09:06:13 AM
I would go with
:notthefirewall:

or
:rtfm:

-Otanx
Title: Re: NETWORKING BASICS
Post by: deanwebb on January 23, 2017, 09:24:02 AM
Agree strongly with Otanx and Ristau. There's a reason those images are in our smiley bank.

Another basic: replace "definitely" with "probably", "always" with "usually", and "that can't possibly happen" with "let me check those settings one more time."

And, if the developers put the network together:

:kiwf:
Title: Re: NETWORKING BASICS
Post by: wintermute000 on January 23, 2017, 05:13:28 PM
(http://i.imgur.com/eAwdKEC.png)
Title: Re: NETWORKING BASICS
Post by: dlots on January 24, 2017, 09:08:21 AM
Is the device you can't ping in the arp table of it's default gateway?
If yes can the default gateway ping it?
If no that means it's almost always a firewall on the end device.

I really really really wish someone had introduced me to the ARP table and explained how awesome it was for troubleshooting when I 1st started in networking.
Title: Re: NETWORKING BASICS
Post by: LynK on January 24, 2017, 10:23:28 AM
yes... systems team. The default gateway does matter.
Title: Re: NETWORKING BASICS
Post by: that1guy15 on January 24, 2017, 01:16:08 PM
Quote from: LynK on January 24, 2017, 10:23:28 AM
yes... systems team. The default gateway does matter.

I have had this conversation way more than I should:

SysAdmin: I cant reach serverX from interface B but can from A
Me: You dont have a route point out B to get there and its following DG out A.
SysAdmin: But both interfaces have a DG set.
Me: Only one gets used. You will need to set static routes.
SysAdmin: Cant you change the network to allow this? I dont know how to set routes in Windows
Me:...
Title: Re: NETWORKING BASICS
Post by: LynK on January 24, 2017, 02:10:37 PM
Quote from: that1guy15 on January 24, 2017, 01:16:08 PM
Quote from: LynK on January 24, 2017, 10:23:28 AM
yes... systems team. The default gateway does matter.

I have had this conversation way more than I should:

SysAdmin: I cant reach serverX from interface B but can from A
Me: You dont have a route point out B to get there and its following DG out A.
SysAdmin: But both interfaces have a DG set.
Me: Only one gets used. You will need to set static routes.
SysAdmin: Cant you change the network to allow this? I dont know how to set routes in Windows
Me:...


LOOOL!!!!!!!

AHAHAHA... that is fantastic. I am glad I am not the only one. I have had this exact issue before.

It gets even better, at my old job we were having an issue with one of the dell chassis, and They kept blaming it on the nexus and its issues. I told them to go in and clear the arp cache on the controller... they snuffed it off as meaning nothing. The next day a sysadmin came over and told me I fixed YOUR issue by clearing the ARP on the chassis. I almost died... hahaha :developers:
Title: Re: NETWORKING BASICS
Post by: SofaKing on January 27, 2017, 12:18:22 PM
Quote from: LynK on January 24, 2017, 10:23:28 AM
yes... systems team. The default gateway does matter.

follow this with -
yes... systems team.  The subnet mask does matter.
Title: Re: NETWORKING BASICS
Post by: SofaKing on January 27, 2017, 12:23:40 PM
Quote from: deanwebb on January 23, 2017, 09:24:02 AM

And, if the developers put the network together:

:kiwf:

When you say "it" I hope the developers are included  :developers:
Title: Re: NETWORKING BASICS
Post by: deanwebb on January 27, 2017, 02:53:36 PM
Quote from: SofaKing on January 27, 2017, 12:23:40 PM
Quote from: deanwebb on January 23, 2017, 09:24:02 AM

And, if the developers put the network together:

:kiwf:

When you say "it" I hope the developers are included  :developers:
Thanks for the feature request, I'll take it back to the BU.
Title: Re: NETWORKING BASICS
Post by: Otanx on January 27, 2017, 03:09:15 PM
DB guys are worse than dev guys. There is a Oracle doc that says you should turn spanning-tree off on your switches because it causes too much delay when bringing a port online. This delay can cause split brain issues in Oracle RAC. I am so glad we got rid of Oracle.

-Otanx
Title: Re: NETWORKING BASICS
Post by: that1guy15 on January 27, 2017, 09:40:34 PM
An old saying I learned applies here.

"No, I dont hate Windows admins, I actually like them. Because without them I would have to manage that shit!"

That is not my circus and those are not my clowns. Now back to routing...
Title: Re: NETWORKING BASICS
Post by: deanwebb on January 28, 2017, 10:56:50 AM
Quote from: Otanx on January 27, 2017, 03:09:15 PM
DB guys are worse than dev guys. There is a Oracle doc that says you should turn spanning-tree off on your switches because it causes too much delay when bringing a port online. This delay can cause split brain issues in Oracle RAC. I am so glad we got rid of Oracle.

-Otanx


This is why, if we put a : before and and the end of oracle, we get:

:oracle:
Title: Re: NETWORKING BASICS
Post by: Dieselboy on January 28, 2017, 12:07:20 PM
My 2901-voice router lives in my TV cabinet. I need to take the top off and vacuum the dust out. Still pretty quiet though, my a/c is louder. (lessons learned: control the dust).

Networking basics:
1. Learn how TCP works
2. Learn how switches, switch

... go from there.
Title: Re: NETWORKING BASICS
Post by: Dieselboy on January 28, 2017, 12:08:36 PM
Quote from: that1guy15 on January 27, 2017, 09:40:34 PM
An old saying I learned applies here.

"No, I dont hate Windows admins, I actually like them. Because without them I would have to manage that shit!"

That is not my circus and those are not my clowns. Now back to routing...

Yep. I've never taken an MS cert. Built and still manage our domain. Learning curve like this: ->   |
Title: Re: NETWORKING BASICS
Post by: deanwebb on January 30, 2017, 09:16:42 AM
Quote from: Dieselboy on January 28, 2017, 12:08:36 PM
Yep. I've never taken an MS cert. Built and still manage our domain. Learning curve like this: ->   |

I had a Windows NT 4.0 MCSE with specialization in MS Exchange.

I *had* an MCSE. Not going to get it again because I don't want to be a sysadmin again. But it *does* help me speak the language and to understand the tribe so that I can help them when their stuff goes down because of a network change they should have paid more attention to, and they come to me with:

:whatudo: