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1500 questions
8
votes
1 answer

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 "universal" configuration in that all switches need to…
YLearn
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1 answer

Is ADSL's UDP packet forwarding rate strictly linear to packet size?

Suppose an ADSL2 Annex A device had a upload speed of 300kbps; tested using a TCP connection. Now suppose I want to send 8-byte UDP keep-alive packets at the maximum possible rate*. Would the effective packet forwarding rate be 4,800 p/s or…
LateralFractal
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8
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1 answer

DHCP-Snooping on 3com S4210

I'm setting up dhcp snooping with IP source guard and DAI on some 3com S4210 switches. I found problem with recording bindings in snooping database. In some cases I know that there is PC connected to interface, it use the DHCP, even switch say in…
skvedo
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8
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1 answer

Cisco PBR verify-availability with interface instead of next-hop

We have a number of Cisco 891 routers configured with dual WAN links. All of these routers are running Cisco IOS 15.x In some cases, we use policy based routing to force particular traffic down one link. I use PBR a lot with Dual WAN setups, as the…
Geekman
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8
votes
1 answer

Upgrading our Network to Managed Switch with Internet Routing

I am a business owner with multiple BT Buisness Broadband lines. We have two sets of VOIP lines and two sets of PC's, each with there own switch board. The problem that we have is that our lines go down frequently and we want to create a simple…
SanSalvage
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8
votes
3 answers

Is it possible to block IKE from reaching a Netscreen's control plane?

I have an issue where a Netscreen 25 is being flooded with IKE packets from an unrelated source, which at times is overloading the firewall's processing capacity. I see thousands of log entries indicating that the IKE messages are being…
Jeremy Stretch
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8
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1 answer

DNS Doctoring / Reply Modification on Cisco 1900 series ISR

We have a Cisco 1900 ISR and have recently setup a web-server at ourdomain.com. The site works perfectly, however from the LAN we cannot use ourdomain.com to access the site, instead everyone has to use the local IP address 10.1.1.xxx. I've come to…
OrangeBox
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8
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4 answers

Multiple sub-nets behind a router

I have 3 simple questions:- Is is possible to have multiple subnets behind a router? I believe it is, e.g. router LAN interface would have subnet mask 255.255.0.0 and machines connecting to the router would have subnet mask 255.255.255.0. Is there…
noi.m
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8
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5 answers

Copy running config in one line

I want to make a script to copy the running config of a switch 4506 in one line. So far, I see two option : copy run tftp: sw#copy run tftp://10.0.0.1/cfg.cfg Address or name of remote host [10.0.0.1]? Destination filename [cfg.cfg]? Cons:…
cgasp
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8
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1 answer

Remote sniffing with ERSPAN to the desktop

I know how to use both SPAN and RSPAN. If I'm not wrong, ERSPAN leads us to the possibility of remotely monitoring a router through an IP network and a GRE tunnel. However a tunnel end-point is needed. My question is, is it possible for the tunnel…
radtrentasei
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8
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2 answers

Basic Catalyst 3560 Egress Shaping

We have a service provider (and we can't change providers) who is giving us a "metro ethernet" style connection between two of our locations. On each end, we plug into an ethernet port on a provider's switch and they ship frames back and forth. We…
Todd Wilcox
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8
votes
3 answers

Map the underlying structure of a VLAN

Is there any way to detect the underlying layout physical layout of a VLAN. For instance, to know whether two devices in the same VLAN are connected via the same wifi AP. To clarify, this would be from the perspective of a device connected to the…
infintejestr
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8
votes
1 answer

Something is filling my force10 ARP table

I have 2 force10 s25 switches that are used for a dark fiber link between two school buildings. One of my switches is filling its ARP table to the brim and then failing. This can happen as often as every 1.5 hours. I noticed that one of the…
MooseBalm
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8
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3 answers

Distributed L3 Switching

Traditional data center architectures centralize the routing. All inter-vlan traffic must transit the core, even when hosts share a network access point. It would be more efficient to perform inter-vlan routing at the network edge. One could route…
Dennis Olvany
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8
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2 answers

JunOS FreeBSD version?

http://juniper.cluepon.net/index.php/JunOS JUNOS prior to 5.0 was based on FreeBSD 2.2.6. JUNOS between 5.0 and 7.2 (inclusive) is based on FreeBSD 4.2. JUNOS 7.3 and higher is based on FreeBSD 4.10. JUNOS 8.5 is based on FreeBSD 6.1 That's all I…
sdaffa23fdsf
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