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1500 questions
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5 answers

Duplicate IP Address - which one wins?

If there's a duplicate IP address, which one "wins"? First, last, flaps, neither?
Pseudocyber
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Configure Cisco ASA in Transparent mode: Layer2 DMZ w/ Vlan translation

I am in the middle of a project to migrate some existing switched ethernet dot1q trunks behind an ASA firewall... these trunks have five vlans each (numbered 51 - 55). This is a simple drawing of the original layer2 service... One of the…
Mike Pennington
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How does a switch know where to route packet, when there is another switch in front of the destination?

I am just wondering how a switch does know how to route packets to destinations "hidden" behind another switch. In my understanding a switch has a table that maps each of its hardware ports to exactly one MAC-address. So far so good, when a…
Jonas Eschmann
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2 answers

Why is my Router's WAN IP different from public IP?

My Router's WAN IP is a public IP - 172.100.x.x And my public IP is - 182.x.x.x Why do I have 2 public IP's? Does this probably mean that my router is behind another router? But then what is the use of configuring 2 public IP's?
GandalfDGrey
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Under what circumstances are multiple loopback (127/8) addresses useful?

I made an app in java where a client sends ip-packets to a server via the looback-address 127.0.0.1. A really simple app just to test how things work. At first I thought If I created several client-sessions new loppback-hosts would be created. But…
Björn Hallström
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6 answers

Ethernet termination density per rack and space planning

I am in the process of designing the network for a new office space. To give a little bit of background... There will only be one network closet to start with potential for an IDF in the future. This closet will have approximately 600 termination…
thefiddler
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4 answers

/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 just using /31 over /30 as it seems /30s are…
knotseh
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2 answers

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 validate my own enterprise IPv4 address space…
generalnetworkerror
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7 answers

TCP acceleration over satellite or high latency networks

What viable companies, products or options are out there today for TCP Acceleration over satellite or high latency IP networks? The average satellite RTT is upwards from 600ms (depends on the location) TCP doesn't work too well as the window sizes…
knotseh
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2 answers

ASICs vs x86 general-purpose routing/switching

SysAdmins often try to convince me that x86 general-purpose OS's can perform just as well as routers with low MHz CPUs and dedicated silicon (i.e., ASICs) at 1Gbps line rates. This thinking is carrying over into the SDN realm such as virtual…
generalnetworkerror
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3 answers

Configure pfSense to not give 'potential DNS rebind attack detected' warning for local server

I am needing to access a local LEMP server through its domain name for a PHP package that uses domain names in every link, making IP address usage not possible for this application. I can access the domain just fine from devices elsewhere on the…
Paul
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15
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3 answers

Why does BGP RR only reflect the best path?

Can anyone answer why does BGP RR only reflect the best path?
Bo Cao
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14
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4 answers

Enabling MLS QoS on a production 7600

I am looking at a 7609-S with a RSP720-3CXL running 12.2(33)SRE3. I have been asked to help with rate limiting some servers attached to a couple of ports running as L2 ports (switchport mode access), so this requires me to apply a policy-map to the…
Baldrick
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Wireless Probe Request Forwarding Best Practices?

I'm working with a couple Cisco WLCs and I know that they use information about client signal strength in determining device locations but I was reading up on "probe requests" and found that, by default, access points will forward probe requests…
David
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2 answers

What is the purpose of BGP TTL security?

What attack vectors does the BGP TTL security knob protect against?
Aaron
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