HP 5412zl - module to module traffic not working Networking

HP 5412zl - module to module traffic not working
MAC Flapping and NIC teaming - How bad?
Study network performance analysis
Got a noob question about dns and reverse dns
RADIUS Issue When Attempting to Test 802.1x
Mesh Networking with Raspberry Pis
How does multihop BGP get traffic to the intended destination?
By default, why does DSCP-based WRED drop DF 0 sooner than DF 8 (scavenger)?
Website loads slowly only for certain geographic regions
Catalyst 3750 to ASA5505 Expansion of Network XPOST from r/ccna

HP 5412zl - module to module traffic not working

Posted: 28 Jul 2018 12:09 PM PDT

Hi everyone,

Has anyone ever ran into issues with traffic not passing between modules in a multi-module ProCurve chassis?

I have an 5412zl where VLAN traffic within a single module works fine, but between 2 modules the traffic doesn't pass at all.

Config:

vlan 201 untagged D19-D24,H18 tagged H20-H24 ip address 10.90.x.x 255.255.255.0 exit

In this example, traffic between H18 and H20 works fine.
But traffic between D21 and H20 doesn't work at all

This is how show module looks like:

Slot Module ---- --------- A HP J8702A B HP J8702A C HP J8702A D HP J8702A E HP J8702A F HP J8702A G HP J8702A H HP J8705A

Any insight into this would be much appreciated.

submitted by /u/TheDerpie
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MAC Flapping and NIC teaming - How bad?

Posted: 28 Jul 2018 05:48 AM PDT

Got a user who insists on running active/active teaming in switch independent mode with members of the teams on separate switches in a switch stack. There are three hosts configured this way.

The switch stack gets upset, because it's seeing source MACs coming in on different ports, so MAC flapping logs are being constantly generated for the involved ports as the switches fight over the CAM table entries.

Since the links are on separate switches, no port-channels. Since they're 2960s, no VPC or VSS.

My opinion is that to stop the flapping, the teams need to be active/passive.

User says this won't work for them because failover won't be totally seamless and some of their critical flows will be interrupted in the event of one of the NICs failing.

Here's the question - how bad is the constant ARP traffic on the VLAN? Assuming about 50 or so hosts on the stack total and only these three teams (six physical ports) doing the MAC flapping.

I'm thinking that the flapping could eventually cause larger problems than a non-seamless failover considering all of the hosts are on the same VLAN that contains the ARP broadcasts.

I'm not sure there's been a day of typical usage yet since the teams were configured recently, and wondering if we may not see the negative effects of the MAC flapping until all the users are working and generating much more traffic.

What do you guys think? Ignore the flapping or push as hard as possible to get the teams into active/passive? Any other possible solutions I've overlooked, you think?

submitted by /u/baudrillard_is_fake
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Study network performance analysis

Posted: 28 Jul 2018 06:23 AM PDT

Hi,

I have recently took interest in the "performance evaluation" side of computer networks, and am currently looking for bibliographical references/video courses/lecture notes teaching this stuff. I am particularly interested in IP traffic analysis and ATM networks performance evaluation.

For info, I come from a compsci background and would appreciate if the material deals, to some degree, with graph/probability theory. However, it doesn't have to be "theoretical-only": some practice in the form of study cases or other would be very welcome (using, for example, packet analysis and network simulation tools).

Thank you very much!

submitted by /u/JamesFrancosHair
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Got a noob question about dns and reverse dns

Posted: 28 Jul 2018 06:42 AM PDT

My company changed providers and got all new ip space. Everything's working on our new ip space but I noticed something odd by chance yesterday. The reverse dns for all our new ips does not match the forward entry

For example if you do nslookup mycompany.com you get back our correct IP address

But if you do nslookup x.x.x.x (our new ip) it shows something like ispsname-static-bunchofotherjunk

Basically forward and reverse don't match. What problems can that cause? The migration happened months ago, and nothing is broken far as I can tell.

Basically if this causes no problems I'd like to leave well enough alone.

submitted by /u/NetworkApprentice
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RADIUS Issue When Attempting to Test 802.1x

Posted: 28 Jul 2018 06:55 AM PDT

I am having a problem with RADIUS on a Cisco 4510. This is the first switch I am configuring with RADIUS. On my NPS the switch is added as a RADIUS client, my switch has the RADIUS and dot1x configs, but nothing is getting through to RADIUS. No firewall on my NPS. I turned on aaa authentication and radius debugging but I am getting no messages logged. Here is the config for the RADIUS part...

aaa new-model ! ! aaa authentication dot1x default group radius ! aaa session-id common ! dot1x system-auth-control errdisable recovery cause security-violation ! radius-server host 172.x.x.x key 7 03160E19070B28595D0C0A06 ! interface GigabitEthernet8/27 switchport mode access switchport voice vlan 100 authentication host-mode multi-domain authentication order dot1x mab authentication priority dot1x mab authentication port-control auto dot1x pae authenticator spanning-tree portfast

Anyone got any ideas what I have wrong here?

submitted by /u/Zombiehotel
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Mesh Networking with Raspberry Pis

Posted: 28 Jul 2018 02:44 PM PDT

Want to create a mesh network using raspberry pi zero ws, only need them to communicate with each other and don't need to connect to the internet, any ideas on what os to use and what mesh implementation to use that will work with the zero w

submitted by /u/NinjaKiro
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How does multihop BGP get traffic to the intended destination?

Posted: 27 Jul 2018 06:17 PM PDT

Say I'm advertising a /24 of 18.0.0.0 to a peer 3 hops away, and my AS number is unique and I have no other peers. I just have a connection out to the Internet from an ISP. I peer with the remote router and advertise my network of 18.0.0.0/24 to that peer, while getting a default route from that peer to send traffic out. No problem so far.

But how does any traffic get to my network? If the remote peer receives traffic to 18.0.0.3, then sends it out using the next hop it uses to establish the BGP peering, the intermediate router between him and me will drop it, because that router has no route to get 18.0.0.3 to its destination at my network.

Does the peer advertise my router's IP as the router to receive the traffic? In that case, the BGP peering is merely for propagation? How would the cost be calculated on the 2 hops that presumably aren't in the BGP table?

Am I missing something here? If not, why would anyone ever peer with anyone that's not directly connected? Johnny Cochran says it does not. Make. Sense!

submitted by /u/HonkeyTalk
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By default, why does DSCP-based WRED drop DF 0 sooner than DF 8 (scavenger)?

Posted: 27 Jul 2018 05:30 PM PDT

By default, why does DSCP-based WRED drop DF 0 sooner than DF 8 (scavenger)?

config:

policy-map QOS

class class-default

random-detect dscp-based

IMG:

https://imgur.com/a/dSekgBr

Notice default DSCP has a minimum threshold of 20 while CS1 has a minimum threshold of 22

submitted by /u/SuddenWeatherReport
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Website loads slowly only for certain geographic regions

Posted: 27 Jul 2018 09:35 PM PDT

(Apologies if this is the wrong place to post)

I am very confused trying to troubleshoot a website connection speed. The site loads fine (<10 seconds) for some and super slowly (60+ seconds, but does load eventually) for others.

There are optimizations I could make to the page to make it load faster, but I'm not worried about tenths of seconds here, I'm trying to solve why it takes 45+ more seconds for some than others.

From my testing, I've concluded it is somehow related to the geographic position of the client that is accessing the site.

Test results (with waterfall of loading times):

Location	Speed (seconds)	Link
New York, NY USA	60+	https://tools.pingdom.com/#!/cMAMbm/http://uprightbuilders.com/
San Jose, CA USA	60+	https://tools.pingdom.com/#!/cY3P1R/http://uprightbuilders.com/
Melbourne, Australia	6.64	https://tools.pingdom.com/#!/cLTnbB/http://uprightbuilders.com/
Stockholm, Sweden	3.94	https://tools.pingdom.com/#!/bwms50/http://uprightbuilders.com/
Dulles, Virginia, USA	4.15	https://www.webpagetest.org/result/180728_CK_94920eb047002fcfc101e0a64a073889/
Chicago, Illinois, USA	4.35	https://www.webpagetest.org/result/180728_AD_113233dbe98a58b4ccf7967f1cbc9061/
New York NY USA	120+ (timeout)	https://www.webpagetest.org/result/180728_SX_105a83765373a6b73070292217f6ec63/

The site is being hosted on AT&T web hosting. It may be tangentially related, but I tried moving nameservers to cloudflare to see if that would help but if anything it just caused it be slow in more regions.

Does anyone have any ideas that I should try? Has anyone seen anything like this before? My next step is to move hosting providers because AT&T says they don't see anything wrong from their point of view.

submitted by /u/illredditthat
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Catalyst 3750 to ASA5505 Expansion of Network XPOST from r/ccna

Posted: 27 Jul 2018 05:24 PM PDT

https://www.reddit.com/r/ccna/comments/92hobf/help_with_vlans_from_catalyst_3750_to_asa5505/

submitted by /u/Fwcasey
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