Questions tagged [interface]

For questions about a physical or virtual interface on a network device. For instance: Interface configurations, troubleshooting and security.

Filter by
Sorted by
Tagged with
5
votes
4answers
8k views

Multiple IP Addresses on VLAN Interface (SVI)

Let's say that there is a SVI for VLAN 100 and it's been assigned the first usable IP address in subnet 192.168.1.0/24. There is a host on VLAN 100 with an IP address of 192.168.1.130. We need to ...
1
vote
1answer
2k views

Multi-area OSPF, Use Wildcard/Subnet IP address OR Quad zero and interface IP address?

I am trying to configure multi area OSPF on several routers (in packet tracer) to a switched core area 0. If I understand correctly, I could either choose to configure OSPF using router interface IP ...
2
votes
2answers
936 views

Ping loopback without interface IP address

I have two routers attached directly and both of them has loopback address. The interface has no IP address, I have just connected R1 g0/0 to R5 g0/0. If I put IP address on the g0/0 interface of both ...
1
vote
1answer
2k views

“Gateway of last resort is not set” even though I have a default route to a tunnel interface

I work with Cisco CSRs. On all of my previous CSRs in AWS, I have the following: AWS-ENV-CSR-R1#sh run | in ip route ip route 0.0.0.0 0.0.0.0 Tunnel1 ip route 0.0.0.0 0.0.0.0 Tunnel2 2 AWS-ENV-CSR-...
1
vote
1answer
59 views

Using different NIC vendors on a LAN - does it make a difference?

I was reading up on network interface cards and came across this statement: "Avoid mixing network adapters from different vendors on the same LAN. Although all may follow a standard, implementation ...
2
votes
1answer
211 views

Can I curl a Cisco sg300 switch to get running config, MAC address table, int des, etc.?

I'm auditing switch interface descriptions at work. I work nights and sometimes people during the day shut down their computers when they leave, so I don't see which computers are on interfaces when I'...
1
vote
2answers
46 views

What are parts of interface name called

Consider this interface name GigabitEthernet1/0/48 I know that GigabitEthernet is an interface type. What does 1, 0 and 48 stand for?
2
votes
1answer
87 views

Can I use a router which has just one working interface? [closed]

I have a Mikrotik RB532 router with three Ethernet ports. One of the ports supports PoE and the other two don't. The main point is that LAN2 and LAN3 interfaces are broken. Can the device still be ...
2
votes
2answers
3k views

Aruba OS equivalent for default interface

I need to reset or default an interface on an Aruba switch. This may be the same for HP procurve switches, but I am not sure. On Cisco, the command would be default interface in global config mode. Is ...
0
votes
2answers
2k views

Address of the router interface in subnetting [closed]

I've been given a Class C address, let's say 192.10.20.0. I have a topology of 4 routers, each with a serial connection to two of the other routers (like a square). To each router is connected two ...
3
votes
2answers
686 views

Cisco: Two interfaces on one network

I'm a newbie to Cisco Equipment and IOS, but got myself a Cisco 2811 and have been playing with it and getting to grips with the basics quite happily. One problem i'm having is trying to get two ...
1
vote
1answer
1k views

Cisco 2811: VLANs, Subinterfaces, HWIC-4ESW

I asked a question not too many hours ago about multiple router interfaces on one network, and I think I have now established what I need to do, however I do not understand how to implement it. For ...
2
votes
2answers
460 views

Manually set combo interface for RJ45 Cisco 3560-CG Series

I have a Cisco Catalyst 3560-CG that has two combo ports with SFP and RJ45 each. Is it possible to manually set the combo port to use the RJ45 only? If so, how is it done? I am troubleshooting a ...
1
vote
1answer
42 views

How to know which IPv6 interface will be chosen by the router?

I would like to know how does the kernel decide through which interface it sends data to some IPv6 address, how is the calculation done based on the routing table information: destination, gateway and ...
0
votes
1answer
57 views

How to assign IPs in server interfaces when connected to two similar routers [closed]

I need to connect two similar routers with the IPs 192.160.2.4/24 and 192.160.2.6/24 (in the same 192.160.2.0/24 network) to 2 server interfaces (ports) in the same server as shown in the image. ...
0
votes
2answers
391 views

Physical interface as switch port and VLAN interface as layer 3 [closed]

In most of large ISP networks, physical interfaces are used as switch ports (layer 2 port) and VLAN interfaces are used as layer 3. Could you please explain what is the main purpose to use like this?
1
vote
2answers
486 views

problem with inter vlan routing with ip helper

here i used the recommendations of making the DHCP server an external server and just use the command IP helper X.X.X.X in cisco 4500X under each interface vlan to relay DHCP to hosts in this vlan , ...
1
vote
0answers
636 views

Interface is up, but wan interface ip not pinging?

I have Juniper ACX-2200 router , i have assigned an ip address to the vlan tagged to ge-0/1/2 interface , and interface status is up, but self wan interface ip not pinging , ip won't even show up in ...
7
votes
2answers
64k views

Difference between CRC and input errors - show interface

The command "show interface fa0/1" prints the following output: What is the difference between "CRC" and "input errors"? CRC errors confirms that a frame error has occured, but what about "input ...
1
vote
1answer
973 views

ARP requests and multiple interfaces

Suppose a device has both ethernet and wireless interfaces enabled and active. Is it correct that ARP requests from one (e.g., ethernet) cannot reach the other (e.g., wireless) unless a Proxy ARP is ...
1
vote
1answer
104 views

what type of fiber SFP for cisco 6500 Gbic module

I have an old 6500 with 6516a GBIC module (picture) and im planning to do some testing with it. I've already looked over Cisco's product page, and im still having a hard time identifying what SFP ...
1
vote
2answers
6k views

What are “Excess Defer Frames” on a show interface gix/x/x controller output?

I have a switch that is counting "output errors". A "show interface gi1/0/46 controller" shows up "2963657 Excess Defer frames" but I really can't find any documentation about "excess defer frames". ...
1
vote
1answer
797 views

Diifference between sfp/sfp+ ports and unified ports

there is something I don't understand. Some switches have SFP ports, it means that you can connect fiber or rj-45 cables I believe? Some switches like Nexus 5600 have unified ports. So they can ...
1
vote
1answer
3k views

Issues trunking VLANs from pfSense to Cisco switch

I am currently using an old desktop with a dual port PCI NIC as a pfSense router. Interface em0 is assigned to the WAN interface, and em1 is assigned to the LAN interface, as well as 3 VLAN interfaces ...
1
vote
1answer
1k views

TACACS: multiple source interfaces

I have a Cisco router connected to a TACACS server via two interfaces. As a prerrequisite, no loopback should be set on the router. My question is: Is it possible to set these two interfaces as ...
1
vote
1answer
659 views

VLAN trunk between Single Port Machine to Switch

i have this setup which is a bit low end because i ran out of test server to test so i'm just doing what i can to attain target setup. Normally i would use a blade or rack type server. So my setup ...
0
votes
1answer
729 views

Configuration interface VLAN hp switch [closed]

my company purchased a new switch brand HP and I created two VLANs on it. VLAN 2 is for the ports 47 and 49 that provide access to internet through a fiber cable and other VLAN 1, which is for the ...
1
vote
1answer
2k views

debugging arp requests over vlan

We have a chain of switches configured for vlan 13, let's call them switch1, switch2 and switch3 No, somewhere on this chain the arp requests get lost. I can run tcpdump on these switches. Running ...
17
votes
7answers
56k views

Cisco command to show which interfaces an ACL is applied to

For Cisco routers and switches, is there a show command, or something similar, that will display what physical and logical interfaces an ACL is implemented on and what direction it is applied in? I ...
4
votes
3answers
9k views

interface down time summary

bar show interface link is there an alternative (pretty) way to display a summary of link last in use. Goal is to get a view of how long a link has been unused. Something along the lines of: show ...
2
votes
2answers
2k views

What are the most common scenarios in which the 'loopback interface' on a router is used?

I was studying about CISCO routers and we learned that every router has a LOOPBACK interface. How and when are those interfaces used? We never used it though in our configurations.
2
votes
1answer
1k views

admin state Vs link state from a network engineer stand point

On a network switch, if the admin state is made "UP" by using a "no shutdown" on that physical interface then it remains "UP" what so ever until the port is configured as "shutdown". This is the ...
2
votes
1answer
55 views

cisco Output Queue Droppped on down interface

what does it mean if an interface is reported down but there are drops on the interface? show interface X displayed: Total output drops: N line protocol is down (notc)
1
vote
1answer
8k views

Overlapping with Serial0/0/0

I have tried configuring the serial interfaces and it is working for two devices which is my HQ1 and HQ2: HQ1 - IP address 120.244.121.136 on Serial0/0/0 HQ2 - IP address 120.244.121.139 on Serial0/0/...
4
votes
1answer
17k views

What is “usec” and “delay” a measurement of?

The term usec appears in the delay field of the show interface command on a router: Router# show interfaces fastethernet 0 Fast Ethernet0 is up, line protocol is up Hardware is DEC21140, address ...
3
votes
2answers
570 views

Juniper SSG and multiple interfaces

Okay guys I have a conundrum on my network, I do not know how it is working, I just know it does. I have a Juniper SSG firewall with 3 different ISPs. I have traffic coming in through the 3 interfaces,...
2
votes
1answer
310 views

Linux routing: routing between 2 local interfaces depends on source address? [closed]

The setup is this: The linux system (debian 7 as a VBox guest) has the following interfaces: $ ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link/...
1
vote
0answers
154 views

Basic Interface MTU Setting [closed]

I would like some clarification on the MTU setting on an interface and the size attribute for ICMP. I have two routers connected directly with an MTU of 1500 set on both sides. There is no dot1q, ...
1
vote
2answers
985 views

Interface on ASA 5525 cannot turn up/up

The interface is connected to a switch and has the no shutdown command applied. The interface at the switch is already up/up, but ASA's interface is still down/down. Another ASA also has the same ...
1
vote
2answers
319 views

Cisco disables port on switch when configures linux bridge

I have a CentOS server plugged into a Cisco 3048. I use nm-connection-editor to configure a virtual bridge interface, like I've done a thousand times before. Every time I enable the bridge, the ...
2
votes
2answers
1k views

Why use two NICs, one external facing and the other internal facing? [closed]

As the question implies, why use two NICs, one external facing and the other internal facing when one would suffice for both functions using NAT.
2
votes
1answer
463 views

Showing the current intput/output rate on a cisco device

Is there a way to check the current interface output/input rate on Cisco devices? the interface statistics only give the average over 5 minutes, and monitoring the interface seems to have a very long ...
1
vote
1answer
2k views

How many network interface can a network interface controller have?

If I am correct, a network interface is the interface between a network interface controller and a network. If I am not correct, please let me know. How many network interface can a network ...
1
vote
0answers
2k views

Get interface input/output rate statistics over SNMP from Huawei switch

We need to monitor the download/upload bandwidth on interfaces on Huawei S5300 switches, and we need to do it with a specific monitoring system. This system can get information from a switch using ...
1
vote
1answer
6k views

I disabled an interface in vyatta, how do I enable it?

I entered set interfaces eth0 disabled which worked. show interfaces shows that the interface is administratively down. However I can figure out how to bring it back up.
7
votes
2answers
3k views

SVI as a DHCP client

Can a Cisco switch be configured to have a management interface (or SVI, or VLAN interface) become a DHCP client, therefore obtaining its own IP address on the respective network? This is out of ...
2
votes
1answer
513 views

Dell 6248P Powerconnect Switch - Routing IP Configuration - What is it for?

This is a rather simple question but I cannot seem to find a resource that explains what this feature is for (without it simply saying "this is to configure an IP interface"....very helpful) Can ...
6
votes
1answer
1k views

Cisco ASA startup-config command ordering for sub-interfaces

In relation to another question on this forum, Moving interface names on a Cisco ASA while maintaining the rest of the configuration in place, I modified the startup-config on my Cisco ASA 5525-X from....
2
votes
2answers
11k views

SonicWall : Blocking Access Between Different Subnets or Interfaces

I have two interfaces on NSA 220 configured as follows Real interface X2 192.168.1.1/24 LAN Zone Virtual interface X2:V1 192.168.2.1/24 VLAN ID 100 LAN Zone In this configuration computers in ...
2
votes
2answers
11k views

Subnetting Question [closed]

Consider a router that interconnects three subnets: Subnet1, Subnet2, and Subnet3. Suppose all of the interfaces in each of these three subnets are required to have the prefix 223.1.17/24. Also ...