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1500 questions
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1 answer

How exactly does TCP react to a retransmission timeout?

Hi! Could someone explain to me what happens at the time-out? Then the window size completely drops. I thought that at time-out the same thing as in 3 duplicate ACKs would happen; half the cwnd and go into additive increase. Is there a difference in…
MSunesson
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Is ICMP spoofing practical?

How practical is ICMP spoofing? scenario 1: in a NAT environment, how does NAT keep track of ICMP sessions (not technically sessions since it's not connection-oriented?) For ECHO/ECHO response Windows use the same identifier (0x1) and sequence…
sdaffa23fdsf
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NMap: Failed to open device eth1

EDIT: I Have found that Nmap can work in unprivileged mode. A question related to that can be found here. I recently installed NMap 6.49BETA4, and the ZenMap GUI, on my Windows 7 Home Premium x64. I'm not familiar with NMap at all, so I expect…
Colin
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1 answer

Ethernet switch capable of H-QoS at the 802.1q level

I have the following type of links at the edge of my ISP cloud: +-----------------------+ | Customer 1 …
mellowd
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1 answer

What are the differences between network, host, loopback and broadcast address?

I have one question about IP addresses. If I have address 172.18.230.127./29 how should I know what type of address is this one. It could be: Network address, Host address, Loopback address Broadcast address What are differences between these…
Lolipop
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2 answers

MST Spanning Tree BPDU`s

I know that MST using regions so that it doesn't have to run multiple instances of spanning tree. However on a trunk are the BPDUs no longer tagged (dot1q) and sent to the neighbor device. i.e are they only sent untagged ? Thanks,
RickD
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2 answers

How to host server in DMZ zone of an ASA

I have an ASA5525-X with 9.1.2. On it are several interfaces, but primarily I'm looking at: (fake subnets) inside 10.0.0.0/24, security level 100 outside 10.0.200.0/24, security level 0 DMZ 10.0.100.0/24, security level 50 I have a DNS server in…
some_guy_long_gone
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1 answer

Junos VRF equal-cost, multi-next-hop static routes not balancing

I am load balancing traffic on dual, same size links aggregating to the same VRF on the PE router (Juniper MX5 JunOS 11.4). Traffic from the CE (Cisco) is balancing nicely but I need get the reverse right. I am not NATing inside the multi-site…
Shawn Gradwell
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1 answer

Sub-interfaces vs. Interfaces

I was recently advised I should not be using VLAN interfaces for connections to upstream peers. On a Juniper MX what, if any, are the cons of using VLANs on an aggregated interface rather than dedicated physical interfaces?
SimonJGreen
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3 answers

1000Base-T Ethernet limited to 100 m, why?

In 1000Base-T Ethernet connection, why is there a 100 m link length limit? CSMA/CD links normally are limited to a few hundred meters because of the limitations that CSMA/CD implies (collision domain size). But with full duplex point-to-point links,…
David
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2 answers

TDMoE and QoS considerations

As mentioned in the previous question I am looking at sending voice communications over a Metro Ethernet connection shared also by data connections. In addition to the previous question I have this one involving QoS guarantees and TDMoE. Voice…
Chris Travers
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Which address should I use to receive a UDP wireless multicast with iperf?

On computer 1 (192.168.1.3): I made a route to be sure that my communication pass through my wireless card sudo route add -net 239.0.0.0 netmask 255.255.255.0 dev wlan2 I launch iperf with the following command : iperf -c 239.0.0.1 -u -l 1316 On…
Vladimir Leiv
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2 answers

A user on 802.1x-protected wireless reports slow or stalled ssh connections

We have recently setup 802.1x wireless at our London location. A user is reporting that an ssh copy between the wireless subnet and our server subnet results in consistently-slowing and eventually stalled transfers. The same transfer across two…
Peter Grace
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What are the SNMP MIBs for Cisco IPSLA ICMP echo

I have two ipsla operations set up: ipsla operation 10 type icmp echo source address 10.0.0.1 destination address 10.0.2 frequency 30 operation 11 type udp jitter tos 128 source address 10.0.0.3 destination address 10.0.0.4 …
John Oxley
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8
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3 answers

Determine what interface is replying to snmp replies

I have a Juniper MX router that is accepting SNMP requests. Problem is I am sending UDP requests to one interface, and it is replying on another. The target IP is that which is assigned to lo0.1 but the router is replying on lo0.0. This is…
Wild Bill
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