Questions tagged [best-practices]

For questions regarding industry methods or techniques that have shown superior results and are accepted as a de facto standard, or have been formally established.

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STP related question

Hi this is a portion of my current set up.. All vlan ports are untagged. Everything works and communicates fine until a connection is made between the 2 switches it takes down the network and the pc ...
Blake's user avatar
  • 13
1 vote
2 answers
130 views

What is the name of the syntax for the "configure" interface?

When accessing routers/switches via ssh cli, I'm familiar with configure syntax but have never bothered to ask "what is it called?" As you might imagine, searches for router configure ...
Josh Hibschman's user avatar
0 votes
1 answer
1k views

VLAN and firewall interconnection

I'm encountering some difficulties to connect some VLANs to a physical firewall. In details I have a core network with a L3 switch as a router and some L2 switches as access network. The network is ...
rouilleart's user avatar
0 votes
3 answers
312 views

Is it best practice to restrict access from non-DMZ hosts to DMZ hosts? [closed]

I know that access should be restricted from DMZ hosts to non-DMZ hosts where possible (i.e., my web servers should only be able to talk to other internal resources where necessary). But is it best ...
sfarbota's user avatar
  • 101
2 votes
2 answers
345 views

VLAN enumeration best practice [closed]

I was looking into VLANs recently and noticed that in several tutorials, VLAN tags with large numeric gaps were chosen, like 10, 20, 30, etc. Is there a reason why one wouldn't simply enumerate it ...
P3trus's user avatar
  • 121
0 votes
1 answer
514 views

Best practice for configuring sampler rate on Nexus 7000 for Netflow

Is there a best practice for configuring the sampler rate for interfaces that will be sending netflow data. I have tested on our Nexus 7000 with the mode 1 out-of 1000 on interfaces that are seeing ...
The Footsie's user avatar
0 votes
1 answer
395 views

Cisco IOS Sanitization: Any Way to Not Use NVRAM?

We want a method to sanitize Cisco IOS 15 routers (ISR Gen 2) before they are removed from the facility. While a "write erase" works perfectly if the router is breathing, how to sanitize dead routers ...
Stephen Craven's user avatar
1 vote
1 answer
121 views

IPv4 Subnetting for 1200 or more devices for WiFi

I am currently looking over my schools existing Subnets and their usage. Some seem to be sufficent, others not so much. What is the best practice when you need to support 1200 or more devices on a ...
Sebastian Bergstroem's user avatar
1 vote
1 answer
1k views

Can communication to broadcast 224.0.0.1 be made to reach hosts outside of the local subnet?

I been asked the question if it is possible for an a IP host to use multicast to address 224.0.0.1 in order to reach (and get a response from) another host which is not on the local network segment ...
IllvilJa's user avatar
  • 228
-1 votes
3 answers
426 views

Can u explain this representation of the IPv6 address 1001::1 64?

::1 is for loopback address. An IPv6 address contains 8 16-bit pieces. What do this representation 1001::1 64 mean (what is the full address with all 8 16-bit pieces)?
kamakshi's user avatar
4 votes
1 answer
2k views

Deploying Virtual Stackwise Catalyst 9400

I am looking into deploying Virtual Stackwise on the Catalyst 9400 series switches. I wanted to know based on best practices where should the VSL links be deployed on the Sups or the modules? Is there ...
vng1203's user avatar
  • 41
1 vote
1 answer
481 views

Is an ACL needed when using PAT (dynamic nat)?

We have a single router (4331) that connects to our ISP. We do PAT (dynamic nat) to give users internet access. Now typically we'd have an OUTSIDE-IN ACL that blocks traffic from the internet. My ...
esafresa's user avatar
  • 246
1 vote
0 answers
30 views

Should static IPs be set on the DNS/DHCP server, the host, or both? [closed]

Assuming a pretty regular business setup, when assigning static IPs for servers to use, should they be assigned on the DNS/DHCP server? Should they be configured individually on the hosts? Or should ...
thanby's user avatar
  • 113
2 votes
1 answer
8k views

Which VPN Types/Protocols inherently support Multicast Traffic?

At my work, we build mobile networks from scratch for customers regularly. (Mobile Networks: think battery powered LTE router with wifi.) Since we build from scratch we can be vendor agnostic and ...
neoakris's user avatar
  • 287
6 votes
2 answers
12k views

Do i need to configure VLANS on my router/firewall or just the switch?

I finally took time to map my entire shitty network to understand exactly what the guy before me did, and i must admit i'm a little bit surprised even if i'm not a network expert... Just take a look ...
Thierry Dalleau's user avatar
0 votes
1 answer
262 views

Best practices for IP Flow monitoring [closed]

Current flow probes (using eg. IPFIX, netFlow v5/9, sFlow) are able to monitor flows defined at least by the tuple < source IP, source Port, IP protocol, destination IP, destination Port, source ...
vera's user avatar
  • 201
7 votes
4 answers
625 views

Building too large for ethernet runs

I'm pretty new to network design. I know enough to wire small buildings and such, but I'm puzzled as to how work this one out. A building I'm working on is an odd shape, and very large. ...
user avatar
1 vote
1 answer
68 views

Managing many L2TP VPNs?

We currently use many IPSec VPNs to connect to separate companies, but the VPNs are managed by a third party. We are interested in running these VPNs ourselves, using any method as long as it is IPSec....
user33278's user avatar
2 votes
1 answer
2k views

Default Gateway Best Practice

Recently I was troubleshooting a firewall issue on one of my servers and noticed that there was a LOT of ICMP redirect traffic being rejected (as it should be). But this got me thinking why I was ...
Caynadian's user avatar
  • 123
1 vote
1 answer
226 views

Best internal(private) ip addressing practices for serial connections (IPv4)

i have the network topology in the diagram below. i was given the Internal address block of 100.1.0.0 for assigning IP addresses. Router 1 has a public ip address to the ISP router 2 i assigned it ...
Swannie's user avatar
  • 25
1 vote
1 answer
4k views

Switch Temperature - How hot it too hot!

I've got a few network switches running rather hot. The switches have an average internal temperature of 63°C. I'm aware that this is too hot for a network switches and we are pushing upper management ...
user avatar
3 votes
2 answers
369 views

Ethernet wiring job done wrong

I am a systems administrator by trade. Though I have done a few wiring jobs, this is not a task that I claim to be a professional at, either by training or experience. However, ethernet wiring isn't ...
ltwally's user avatar
  • 131
8 votes
6 answers
26k views

Best practice - Set static IP in device or router?

Pretty simple question. What is the industry best practice? In a small business which has computers which require static IP addresses is it better to set static IP addresses for devices on the ...
Joshua Michael's user avatar
1 vote
1 answer
4k views

General best practice for VLANs and domains

I recently took a job at a school. This is only my second position as an IT professional. My only experience with corporate networks is in a large school district at another school. They used VLANs to ...
user999861's user avatar
2 votes
2 answers
217 views

Building New Network and Need fast connection to central database between 20 wired and 20 wireless devices

I'm planning the network for my company's new office space. I'm not an expert so I'd like to present my plan and ask y'all nice folk to tell me if and where I'm making mistakes. Assumptions: Office ...
Brooke Johnson's user avatar
3 votes
5 answers
1k views

Reason behind having a separate network for firewall interfaces?

Just wondering the theory or reason behind having the inside interface of a firewall on a different network than your primary network. I put together a quick drawing of what i'm talking about. What ...
Matt Fogleman's user avatar
4 votes
2 answers
14k views

Ethernet keystone jack color conventions?

In a similar vein as this question... Are there any conventions or standards that recommend a color scheme for the colors of Ethernet keystone jacks?
cp.engr's user avatar
  • 141
9 votes
2 answers
2k views

Which QoS classification should be applied to NTP?

Cisco's Enterprise QoS Solution Reference Network Design suggests classifying NTP as network management traffic and marking it as CS2: When addressing the QoS needs of Network Management traffic, ...
Stephen Craven's user avatar
1 vote
1 answer
2k views

Network engineers - What are some specific layer 2 network problems you have seen? [closed]

The networking industry has come to a general consensus that large layer 2 networks are more troublesome to build and maintain because of the inherent problems in the layer 2 switching. To name a few ...
Manohar's user avatar
  • 113
5 votes
1 answer
220 views

Internet exchange point

My edge router is connected to one transit ISP full route table and to IXP. I would like to know what is the best way to protect the connection to IXP from becoming unwilling transit ISP. For example ...
Vasisl's user avatar
  • 51
5 votes
1 answer
3k views

VLANs: To Prune or not to Prune

I was pondering my network design today and came upon an idea that makes lots of sense to me, but I fear that it may be a terrible idea. I just don't have enough knowledge or experience to convince ...
PacketWrangler's user avatar
2 votes
1 answer
181 views

Best Authentication Practice

We are setting up a new network at work, when the building was comprised mostly of desktops, life was simple -static IPs for everyone. As the company moved to wireless laptops, they began keeping a ...
HashHazard's user avatar
8 votes
2 answers
24k views

Single Access Point vs. Multiple Access Points

Vague Question: If one access point can do the job adequately is there still an advantage to using more than one? Scenario: 1 access point at the center of your network required coverage area should ...
David O'Brien's user avatar
3 votes
1 answer
7k views

hp procurve trunk port group operation vs active lacp port group

We recently purchased some HP Procurve 2920 switches and in setting them up I noticed multiple options for port groups. I wanted to see if anyone can clarify functional differences between setting up ...
Mike Naylor's user avatar
3 votes
1 answer
459 views

Cisco router dot1Q monitoring

How can I monitor on a Cisco router if dot1Q packets arrive on the trunk interface or if others arrive on that interface (like ISL, the old protocol of Cisco)? How can I do this and what is the best ...
Bulki's user avatar
  • 2,383
20 votes
5 answers
100k views

Cable Colors and Purpose

I've been doing some work with some big businesses and so far I've learned yellow is internet and blue is phone. Is this a standard or is this just a personal chose? Do colors mean different tasks?
Jason's user avatar
  • 1,015
11 votes
3 answers
1k views

Do today's routers prevent fake IP headers?

I know people can modify the IP headers and change source IP address, but it should be simple for network devices to detect those messages. If they don't, why is it so hard? Does it add too much ...
Nachos's user avatar
  • 267
18 votes
7 answers
13k views

Best practice for the combination of HSRP and ECMP

The combination of ECMP (or other causes of asymmetric paths) and HSRP is broken by default in Cisco IOS; the default behaviour with this design floods unicast traffic excessively. What is the best-...
Mike Pennington's user avatar
15 votes
4 answers
5k views

/31 Point-to-point bitmasks

When is it appropriate to use a /31 network in production, and is using them considered good practice? On a point-to-point link, broadcasts shouldn't be required, so is there any compelling case for ...
knotseh's user avatar
  • 2,535
15 votes
2 answers
8k views

IPv4 Address Space Planning Best Practices

A recent question from Craig Constantine pertained to IPv6, but many people are not on the leading edge with IPv6 yet and are still responsible for new or improved IPv4 deployments. I would like to ...
generalnetworkerror's user avatar
10 votes
1 answer
8k views

What factors drive L2 vs L3 in the access layer?

When designing an access layer, best practices today seem to indicate going toward a L3 design. I know the answers may be different depending on whether or not we're talking about a DC design or ...
generalnetworkerror's user avatar
4 votes
4 answers
1k views

OSPF LSA Performance Tuning

Does it make more sense to modify the 1800 second refresh rate, pacing timers, or all of the above in terms of network stability/best practices/etc to achieve quicker LSA maintenance? I am dealing ...
THE DOCTOR's user avatar
19 votes
3 answers
9k views

What factors drive a Cisco IOS upgrade?

In order of preference/priority, what factors do you consider in driving an upgrade (or downgrade) with Cisco IOS? If no compelling factors exist, how long would you allow a particular version of IOS ...
generalnetworkerror's user avatar
11 votes
2 answers
19k views

Preventing STP loops in etherchannels configurations

What is the best practice when configuring etherchannel on Cisco switches to prevent a STP loop/broadcast storm when etherchannel is mis-configured? I had an instance where 2 ports on a switch were ...
knotseh's user avatar
  • 2,535
21 votes
7 answers
7k views

Building new network and need 200+ wireless devices

I'm planning the network for my company's new office space. I'm not an expert so I'd like to present my plan and ask y'all nice folk to tell me if and where I'm making mistakes. Assumptions: Office ...
SAR622's user avatar
  • 693
5 votes
1 answer
7k views

How to disable 802.11b wireless clients on my WLAN?

Most wireless vendors recommend that unless there is a need to support them, 802.11b should be disabled on the network. How should I go about disabling 802.11b on my network?
YLearn's user avatar
  • 27.3k
6 votes
3 answers
3k views

Monitoring best practice for thresholding errors on an interface?

When monitoring interface errors, what percentage of traffic should you set your 'critical' threshold to according to best practices and does it depend on the interface type (T1, Ethernet etc)? It ...
billcobbler's user avatar
7 votes
6 answers
6k views

What is the benefit of a Cisco "top of rack" design?

Aside from the obvious cabling mess you avoid (which I know for us as network engineers is great, but hard to use as an excuse when reasoning with someone who sees no point in it), what do you gain ...
skrumcd's user avatar
  • 216
13 votes
4 answers
2k views

Is a wireless only network (for end users) a viable option?

We are constructing a new building, and our CIO is pushing for a solution where he doesn't have to spend the money on copper runs to all the user stations and wants to use wireless only for this ...
YLearn's user avatar
  • 27.3k
8 votes
1 answer
2k views

Migrating from STP short mode to long mode?

It was decided recently to migrate a large campus network from the short mode STP costs (16-bit) to the long mode STP costs (32-bit). I have clearly found it documented that this needs to be a "...
YLearn's user avatar
  • 27.3k