Hot answers tagged

8

Cisco 2960 switches pull in cool air from the sides and exhaust to the rear. Depth-wise they are 1/3 to 1/2 rack-depth (depending on exact model switch and rack). This leaves you very few options. If you mount them unmodified backside of the rack just about the entire switch is in the hot zone. That will only be OK if you have cold airflow running on the ...


7

I noticed (based on activity lights) that VLAN traffic between two switch ports are being sent to many switch ports. Seriously? That's not how to determine traffic flows. The activity lights could be active for any number of reasons. Because Host 1 and Host 2 are in different VLAN's then they must be in different Layer 3 subnets as well. The only way they ...


5

IPv6 doesn't use ARP. It uses Neighbor Discovery (ND), which uses ICMPv6. Proxy-arp was used for IPv4 networks where some devices had a wrong subnet mask. The proxy-arp feature on the router would reply to ARP requests for off-net addresses so that such clients would send their traffic to the router so it would actually act as a default gateway. In IPv6 you ...


5

It's not a router problem and it has nothing to do with the "Cisco world". You can host multiple websites on a single web server all on port 80 via a single ip address by using Host Headers (or the Linux equivalent).


5

Administrative distance is the feature that routers use in order to select the best path when there are two or more different routes to the same destination from two different routing protocols. Administrative distance defines the reliability of a routing protocol. List with routing protocols and administrative distances: EIGRP 90 OSPF 110 RIP 120 In ...


4

He is absolutely correct. Netgear switches are crummy and cheap with low manageability and tiny packet buffers. You're trading capex for opex. Cisco SMB switches are essentially a small step up from Linksys. Catalyst are pricier, but if you want your network to work and be manageable you need something in that class. For a tech company, a network is ...


3

Q: Can layer 2 switch ports be configured as VLAN trunk ports? A: Most certainly. VLAN's are a Layer 2 construct. Q: Do I have to set both ends of the trunk as a trunk? A: Yes. A few things to note: You need to make sure that both sides of the trunk have the encapsulation configured as 802.1Q. I can't give you specifics on how to configure the trunk on ...


3

With the strict hot/cold setup it seems like even if the airflow could be reversed leaving the switches at the back of the racks would have a negative impact since they would be sucking in air from the hot aisle in the datacenter. Based on the diagrams of the switch that I can see online it is not a full depth switch, so when mounted on the back side of the ...


3

Appreciating this is an old question, and that it's already been answered - I did trip across it while frustratedly trying to determine what the "real-world" performance of some second-hand routers off eBay would achieve, and Google kept bringing me here. As the accepted answer states - the Cisco data-sheets (notably this comparison of major router models) ...


3

The purpose of load balancing is not for a scenario where there's just one AP. It's intended for a scenario with multiple APs. When you set up multiple APs, you always put them not-too-far from each other. You want the APs to overlap, a little, to be able to hop between APs. You don't want one APs signal to completely die out before getting into the next APs ...


3

Did you issue the following commands? Enable the HTTP server for ASDM http server enable Allow the management host(s) to access ASDM http management_host_ip mask interface_name After doing the above in configuration mode, access ASDM from Firefox browser (you need to have Java JRE and Java browser plugin installed) using the URL https://<...


3

In reverse order... Your routing table is actually correct. The L flag means that is the IP address local to the router on that link, while the C flag means that network is attached to the router on that link. The problem would be that your modem doesn't know that the 192.168.10.0 /24 network is reachable via 192.16.1.69, or doesn't have a NAT policy for ...


3

The key problem seems to be a missing bgp dmzlink-bw option under the address-family in the configuration. Let me, however, summarise my comments here: bgp dmzlink-bw under address-family. neighbor dmzlink-bw only enables advertisement of bandwidth to neighbours, whilebgp dmzlink-bw enables proportional load balancing itself. Running-config had bandwidth ...


3

What you're missing is: First, ICMP, at least in part, is required for proper functioning of the Internet. Second, blocking pings is completely pointless; it has no security benefits whatsoever, and can cause you trouble later on when you decide you need to be able to ping your device from outside for troubleshooting or other reasons. If you're really ...


3

Sure, for microseconds it lives in some buffers so that the routers can check it against ACLs and match it against its routing tables (technically it only needs the headers for performing these actions, and thus could do it on a cut-through method), or buffering it for a slower connection on another link. If there is ethernet in the mix, it will likely live ...


3

VLANs, by default, can only talk to themselves internally. Let's change your setup a bit--- let's disable ge5 and turn on ge3, and make ge3 part of VLAN 101. From a computer directly connected to ge2, you can communicate with another computer on ge3... but you can't communicate with anything on ge1, because it is on another VLAN. Let's turn back on ge5--- ...


2

I've just answered a similar question at https://supportforums.cisco.com/discussion/12102421/nat-hairpinning, let me repeat the answer here: First of all, such a situation is encountered often enough. Second, while NAT theoretically may be a solution, in practice particular vendor implementations of NAT can be restrictive and fail to support this. One ...


2

If it is OK for you to change the default gateway of your clients to fail-over, you just need to configure 192.168.10.236/24 on your VDSL router's LAN interface and connect it to your switch (note that if your are using DHCP, you should probably also disable the DHCP server in the VDSL router so you don't have two DHCP servers in the network).


2

Even though the device supports it, Cisco by default uses what I call "compatibility mode" for AAA, where it limits the feature set to the "old model". Use the aaa new-model, then try again.


2

I dont think a wiring issue as it copy, and always fail at the end. Remove your antivirus to test out, as it look to me a scanning error


2

One cheeky and simple way to do this is to use two switches rather than one. You could then uplink half of your devices to one switch and half on the other, and thereby double your total throughput. If you then require more outgoing throughput from a single server, you could bond the two interfaces with uplinks to both switches in your room. Just make sure ...


2

You are nmapping the cisco router, so you are checking the open cisco ports, not the open webserver ports behind it. If you nmap the webserver you'll find port 80 open.


2

This looks like TCP sync flooding attack. You need to find out the TCB numbers to be able to clear the sessions. The Transmission Control Block (TCB) is a transport protocol data structure (actually a set of structures in many operations systems) that holds all the information about a connection. The memory footprint of a single TCB depends on ...


2

Well, the NAT rules don't seem to be correctly set up. The port forwarding concept for Cisco ASA is a bit tricky: Port Redirection (Forwarding) with Static Port forwarding or port redirection is a useful feature where the outside users try to access an internal server on a specific port. In order to achieve this, the internal server, which has a ...


2

Unless it is absolutely necessary, which I doubt, running layer-2 over a WAN is a really bad idea. STP will require all sorts of tweaks to work correctly with the increased latency. You need to measure the latency and apply it to all the STP calculations. Broadcasts, multicasts, and unknown unicasts will need to travel end-to-end to every switch port in the ...


2

When you have a stack of switches, you want to create a loop with the stacking cables. Port 2 on one switch connects to port 1 on the next switch. Continue that until the last switch which will connect back to the first switch. This creates a loop in the switch connections. When you lose one link in the loop, you will still have a continuous link between ...


2

The first icmp packet is fail because host sends ARP request. If the destination host MAC is already in ARP cahce the device is not send this request.


2

There are no actual firewall rules here, these are just name -> IP address (range) mappings used in the configuration to make the configuration easier to read. However, most likely the original consultant wanted to leave some flexibility for the IP address, in case the IP address of the incoming connection changes. If you are sure that the inbound ...


2

The part of the configuration you posted does not contain NAT rules or ACLs (both of which are related to allowing a remote IP to print to a printer in your network). object network vendor-srv-PrintingVendor This is a network object. In Cisco routers you can define network objects by name so that you do not have to remember the IP addresses. So for the ...


2

Do you really want all that superfluous traffic to and from your domain controllers going through all that network equipment? All the encapsulation, decapsulation and circuitous routing is really going to limit your throughput and leave less bandwidth available for all of the other devices that need to share that network. I'd think long and hard about some ...



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