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1500 questions
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5 answers

Why does NAT translate a source port?

I’m beginning to learn about NAT and I was wondering: Why does NAT translate a source port? Doesn’t a port represent an application that’s requesting a service? So why must it be translated? Also what would happen if NAT hypothetically didn’t…
Jaffa
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8 answers

Can Ethernet frames only be transmitted in a LAN?

In the LAN depicted in the picture below, am I correct in saying that devices do not have IP addresses? There is no router and also only Ethernet frames (with source and destination mac address would be transmitted) and not IP packets. Is that a…
TomTech
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3 answers

Does varying the angle of omni directional antennas affect connection quality between WiFi APs?

I use Cisco access points AIR-CAP1552E to connect buildings via WiFi, 802.11a/n (5 GHz). Normally, they are mounted upright, with three three omni directional antennas at the bottom. Now I consider a single AP on the roof of a very small building,…
Stefan
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9
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4 answers

Cisco-configuration syntax highlighting for TextMate/Sublime Text

I would like to have syntax highlighting while perusing my configs - does anybody know of a good Cisco IOS syntax highlighting bundle for TextMate or Sublime Text? Edited (2015-09-21) to add: GitHub Atom Editor has a Cisco IOS syntax highlighter in…
Jan
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9
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4 answers

How would a firewall kill a TCP connection without RST or FIN?

Situation is like this: http client ----> corporate firewall ----> http server Due to a keepalive, server and client would keep TCP connections open and the client would use a connection pool for HTTP requests. The firewall has a rule to "kill"…
cen
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9
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4 answers

The maximum length of CAT6 for intranet network?

Recently I purchased CAT6 cable with a length of 150 meter. I bought another CAT6 with a length of 148 meter. I joined both the cables using RJ45 cable coupler. I tested it using LAN TESTER, and everything looks normal. One of the end of the cable…
Mawia HL
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9
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3 answers

Implementing Cisco QoS model to end users

I have implemented the 4-Class QoS Model as described in this earlier post from 2013. This Core configuration is implemented on a Cisco VSS 6509-E setup running software version: Cisco IOS Software, s2t54 Software (s2t54-ADVENTERPRISEK9-M), Version…
user36472
9
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1 answer

What happens when a subnet reaches capacity?

Other than not being able to claim any more IP addresses in a subnet, what other bad things happen when a subnet reaches 100% utilization, if anything?
UnworthyToast
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9
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1 answer

Method for assigning IPv6 ULA addresses to LAN

I'm finally embarking on the voyage that is IPv6. I am not sure however, on the best way of assigning a unique local address (ULA) to each host in my LAN. For IPv4 I prefer to have a DHCP server with all the mappings between MAC addresses and fixed…
Malvineous
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9
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1 answer

Unexpected AS-PATH ACL behavior

4 routers, lab environment. Trying to filter out routes originating from AS2 (not that leverage AS2 as transit). The process I've followed is: Bakers#sh ip bgp regex _2_ BGP table version is 41, local router ID is 33.33.33.33 Status codes: s…
A L
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9
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1 answer

TCP Client / Server in Cisco EEM 3.0

I'm attempting to set up client / server sockets in Cisco EEM 3.0 TCL with IOS version 12.4(24)T8 (this was recently upgraded to determine whether the problem was EEM ver). I have the following two example Tcl scripts (ref: http://wiki.tcl.tk/15315…
Tarah
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9
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4 answers

Does IPv6 remove the need for a VPN?

I know that a VPN may be used in lots of different ways for lots of different things, so I'm not suggesting that IPv6 removes the need for a VPN completely. I'm interested in one particular use-case: I have a cellular (GSM) router, and…
banjaxed
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2 answers

How can hosts with public IP addresses have nodes with private IP addresses in their traceroute?

I'm doing some research on users connected to Internet via cable operators and I've seen some unusual route traces. A bit about setup: Basically user has a home router connected to a DOCSIS modem. The router seems to receive a public IP address from…
AndrejaKo
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9
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2 answers

What are common sizes to split a /29 - /32 IPv6 subnet?

As an LIR, you are getting a /29 to /32 network allocation by the RIPE, but I am a bit overwhelmed by the size of this subnet, and don't find a starting point to split this into common sizes. What we need to address with this subnet: office…
Maximilian Ruta
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9
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2 answers

Does Juniper set a control word on VPLS pseudowires

At the RIPE conference the was a talk about how MAC addresses starting with a 4or 6 may suffer from decreased performance because MPLS routers misinterpret the Ethernet packets as an IPv4/6 packet when load balancing over multiple…
Sebastian Wiesinger
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