Cisco switch port keeps going up and down. Any suggestions? May 28 10:29:38.

Cisco switch port keeps going up and down Below is the example of those po May 3, 2021 · A port flap, also referred to as a link flap, is a situation in which a physical interface on the switch continually goes up and down, three or more times a second for duration of at least ten seconds. I have tried different cables in different ports but only one (f0/6) is lighting up. I changed out the cables with new cables and it didn't fix it. However, only the first VLAN I configure (currently VLAN 1) will get to an up/up state. what could be the cause? Long story short, I'm a server admin, trying to play network admin right now and solve an ongoing issue. Sometimes when you configure a monitor (SPAN) session, the destination interface shows the down status (monitoring) by design. I'm seeing frequent flaps where the port goes down, stays down for a few seconds, and then comes back up. 1. Multiple ports are going up/down all at the same time, knocking devices offline. This instability caused by flapping ports affects network connectivity and degrades the end-user experience. VLAN1 is the defaul Aug 18, 2022 · Hi All, I have found one of the port has no night and it showed the interface down\\down (notconnect) on the 2960 cisco switch. As soon as I enabled the port, the LAG showed both ports as active and the flapping on all the other ports stopped. Under certain circumstances, interoperability issues between Cisco switches and various NICs may result in continuous or intermittent link up/down situations. Close CAPWAP DTLS session. Oct 23, 2020 · I noticed that one of the ports on the Fortigate side was disabled, so the LAG and LACP was UP on the cisco but only utilising 1 port with the other showing as “standby” on the cisco. for example if the switch is layer 2 only then the router would have a sub interface wiht the ip address on. Nov 16, 2024 · Hello everybody, I have an issue with one "redundancy link" in between one of my service building and my secondary site. For some reason the port on the cisco switch they are connected to randomly shuts down and the light goes off as if nothing is connected to that port It's up/up for a while but suddenly it becomes up/down. Keep in mind that if you see any unnecessary config don't feel bad to point it out. These link up/down situations are usually a result of power management features or jitter tolerance issues associated with the NIC Nov 23, 2011 · Hello All We got Issue with One Access Point [ model - AP1242AG ] - it goes up/down. The rest are showing all as being down when I try to assign it an ip Yesterday I noticed that the ethernet Port on my notebook was going down (network lost) and then up again within a few seconds. Any ideas? Yared Aug 25, 2021 · Hi all, I've noticed the below on our core switch to edge switch connection since forever really I'm wondering if it's some sort of load balancing or if it indicates a problem ? The Core is a pair of stacked SG350XG-2F10's and the edge is a stack of 4 SG350X-48's. Ports keep going up and down is it normal severity (error) ? See below ´ Apr 26, 2021 · Hello, I have a really big issue with port channel members going down for no reason and coming back up again. Do you have any config other side ? rukush side how the port configured ? Aug 17, 2006 · I'm configuring a new switch for multiple VLANs, each with their own IP range. When this happens to both ports, the po goes down offcourse (2 members per port channel). I have checked many switches that are located in different buildings and these had same kind of logs! Ports going Up/Down on regulars basis. Feb 28, 2019 · Hi Guys, My company is using IPT phones model CP-7821 For the past 2 weeks we've been noticing some strange behaviors with certain phonesOnce plugged they display "Network Unavailable" and if we take a look into the switch interface and keeps changing from up to down (connected/notconnect). 960 EST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Gigabit Ethernet0/7, changed state Oct 26, 2017 · I’ve just looked at the diagnostic logs on one of my switches and the port state keeps changing from up to down. We installed a NIC in the users PC and now the PC is able to connect to the network ok. May 10, 2020 · NIC Card on your devices. All the usual stuff has been tried the other router has no such issue when cabled to the other layer 3 switch at our site. At the same time, trunk port and port connected to server are stable. I have 14 other remote locations workling fine. A broken fiber cable or other cabling/port issues can cause this one-way only communication. 031695: Sep 21 10:56:04. Do you have similar issue I recently started at a new Job and they're using Hadoop with Cisco switches at the Data Center. Nov 28, 2024 · Devices: EWC Model: Cisco 9115AXI-E-EWC (version:16. Logs indicate: Heartbeat timer expiry for AP. Nov 8, 2005 · I have an 1841 router and a 2950 switch and VLANing/trunking from scratch for the first time. These partially functional links can cause problems such as STP loops when the switches involved do not know that the link is partially broken. I want 3 VLANS on the switch. On a big industrial plant we've replaced an old HP switch with a brand new couple of C2960x switches in stack configuration and ever since then, every 6/8 hours or so, the two fiber optics links of switch #2 go down at once. 4a) CAPWAP APs: Cisco 9115AXI-E (version:17. Jun 15, 2016 · Hi, We have our remote offices Core switches pointing to our syslog. Worse scenario, if you have another switch working great, swap that one to the same position and see if it keeps happening, that will rule out hardware problems. Jan 28, 2008 · I just set up an L2 port channel for testing purposes to a server using two GigE links. ROUTER1GW# May 13 13:35:51 EDT: %OSPF-5-ADJCHG: Process 10, Nbr 10. Typically if there is a connection to a router there would be only 1 link per vlan. The access-point was installed around 3-4 weeks back. The WAPS attached have two networks: a Guest Vlan 20 and a connection to my network for non-guest users. Ports on going up and down on multiple switches, Could you please share your thoughts ? Sep 15 14:55:09. 857: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/16, changed state to down Apr 16, 2003 · I have a serial interface that goes up and then back down about every 30 seconds. Observed errors:. Users connected on this Access Point get disconnected or time-out connecting to Server. We checked the cable connecting to the Access Point but didnt notice li Also, if you can keep monitoring the port and trying to get the MAC address from the MAC table (assuming there will be some traffic on that port) you can then report the issue to the datacenter guys specifying the MAC address of the connected device so they can verify what is going on. This has been seen with 3Com NIC's as well as some others. Sep 10, 2022 · In one of our customer's switches (C9300-48P-A), when the PC connected to a port goes to sleep mode, we can see in the logging that the port is flapping up and down every 1-3 minutes. I've never seen anything like this before so I was wondering if any of you have. Jun 18, 2021 · If a port is going up adn down it is usually a spanning tree problem. I have a cable in 10Gbe uplink Apr 14, 2023 · Hi. Here is the logging! From one switch which shows what happens, the same port is going up and down many times and it is not about one switch or one user. The end device of the port is a sharp printer. 30 fr May 12, 2005 · No, only this one management VLAN interface has to stay up at all times. Any help would be appreciated. (Line down/up) Layer 2 goes down and then up. Network admins can use this file to easily identify the specific port and its networking attributes and troubleshoot the port flapping. The configuration on both of the physical interfaces is Jan 7, 2013 · The common causes for ports to go up/down may include Spanning tree (such as root bridge elections or max age time out tables resetting) Negotiation (speed/duplex) Discovery protocols such as bonjour Over utilization (system resources or Layer 3) Firmware problems If it is at all possible, I'd break the stack and have the switches standalone. Off our core 9300-48UXM, one off the SFP ports with a GLC-LH-SMD in the network module just quit working, taking its access switch (2960) down. . 5. I thought it was dead but I adopted it to my home network and it works just fine. Any suggestions? May 28 10:29:38. May 30, 2017 · Solved: I am setting up my 2960 switch and only 1 of my ports is showing a status of being up. The OSPF neighbor relationship between 2 routers keeps dropping, then immediately reforming the adjacency. I tried to reload the switch and change the cable still not working. They mention that randomly one of the ports in the bonded pair will go down and randomly come back around 5 minutes later. I've read this may be related to the clocking (which I've already check is the same both in the terminal emulator and the usb port used as serial) or the encapsulation done differently, although I've no idea how to check this. This is a 4500 switch . Also i cannot trunk it to some random user port with native vlan being user vlan, because it can go down too, and i want to have all user ports clean, in access. Oct 21, 2024 · I have a customer that has a number of Cayalyst 9200 switches (C9200-24T, though some are 48-ports). Problem is this happens to 3 of the 4 SG350x series switches installed like this atm, so not isolat May 26, 2017 · I am a novice with Cisco switches – I have a switch with some ports that keep oscillating between up and down: Here are the settings on port 1/0/22: How do I diagnose this problem?. We want to stop receiving port up/down message on syslog. Layer 1 goes down and then up. 12. 513 MEST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/12, changed state to down Feb 17, 2025 · Power down the switch, pull the power supplies out and wait for the power supplie's fans to stop spinning. Same behaviour when a PC wakes up from sleep. I have checked many switches that are located in different buildings May 26, 2017 · I am a novice with Cisco switches – I have a switch with some ports that keep oscillating between up and down: Here are the settings on port 1/0/22: How do I diagnose this problem? spanning-tree portfast trunk spanning-tree bpduguard disable sh int gi6/14 gi6/14 is up, line protocol is down (monitoring) can any one help please? Dec 3, 2019 · Solved: Hi there, According to syslog, one port of one of our switches keeps flapping. I am positive all of the cabling is good. one option is to disable log Dec 2, 2008 · I have a cable that is not labeled and when I unplug it from the computer I want the switch to tell me that the port goes down and when it is plugged in I want it to tell me the port came back up. All other VLANs I've added stay in a up/down state and I'm unable to ping the interface's assigned ip address. Spiceworks Network Monitor also shows massive packet loss. Nov 8, 2012 · Hi i am just wondering, we hava a couple of 2960 switches and we are logging to a syslog server. 681 BST: %LINEPROTO Dec 2, 2008 · I have a cable that is not labeled and when I unplug it from the computer I want the switch to tell me that the port goes down and when it is plugged in I want it to tell me the port came back up. Currently it doesn't cause an outage because Nov 13, 2019 · How is this even possible? … and has anyone else seen this? One bad connection on a small comms closet switch causing outages across an entire campus network (5 switches connected in a star by fiber or copper at gigabit speeds). Is it possible that there is an issue Frequent status changes from up to down or vice versa in the ports logged by the switch port syslog indicates a port flap. Both of the interfaces are showing up/up and passing traffic, and seem to be load-balancing correctly, but the port-channel interface is showing down/down. Symptoms: CAPWAP APs fail to stabilize and keep flipping (UP/DOWN). The overwhelming amount of packet loss and increased latency due to this constant rate switching often causes massive degradation in the network performance. it is only possible to have the same vlan ion multiple interfaces by bridging and Dec 15, 2012 · The switch does not know that the link coming back is bad (the port thinks the link is up and working). 857: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/16, changed state to down Mar 17, 2011 · Hello, A users port keeps going up and down. What causes this sort of behavior and what can I do to resolve it? Syslog logging: enabled (0 messages dropped, 1 messages rate-limited, 0 flushes, 0 overruns, xml disabled, filtering disabled) Console logging: level debugging, 16111 messages logged, xml disabled, filtering Jan 17, 2018 · With individual ports showing these changes and client devices are connected to it it can mean that the port went down/up for a moment or that the client device stopped sending packets for some time, then traffic was once again seen sent by the client. Our desk Oct 14, 2003 · Here is information from Cisco's web site. Port flapping, also known as link flapping, causes a switch port's state to fluctuate between up and down within concise periods of time. All of my VLANs have Nov 3, 2023 · This document describes how to determine why a port or interface experiences problems. And i cannot trunk it to the uplink interface because there are multiple uplinks, and also the VLANs are reused within management domain, so i want to keep I tried a different cable, reset the AP a few times, and even tried wiring it up to a different switch but nothing seems to work - it keeps flapping up and then going offline every 3-5 minutes. I try to add a link between 2 switches and when I no shut the interfaces the interface in my service building is going UP/UP and the interface facing it stays DOWN/DOWN. Jun 16, 2022 · I got many users complaining that they are loosing the connection very often. Th Feb 5, 2019 · When you connected to laptop what speed you see on the laptop. The problem is that I can make the 10G link work, but it just turns off after a few hours without a clear reason, and then I have to shut the port down May 26, 2017 · I am a novice with Cisco switches – I have a switch with some ports that keep oscillating between up and down: Here are the settings on port 1/0/22: How do I diagnose this problem? May 26, 2017 · I am a novice with Cisco switches – I have a switch with some ports that keep oscillating between up and down: Here are the settings on port 1/0/22: How do I diagnose this problem? May 13, 2021 · Hello all, I am having an issue to which I have not really be able to find a cause or resolution. 922 BST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/31, changed state to up Sep 15 14:55:17. Problem is that those Core switches has servers/printers that keep going up/down through out the day , and we see ports up/down alert on syslog. May 17, 2016 · How many switches do you have; and are they all configured similarly to the one given? Do you still have other switches (hubs) in the environment? Is there any possibility that you have redundant links between the switches, and potentially causing a loop? (i. 9. 4) Switches: Cisco 9200L-48P switches. Got a call late Friday from a co-worker that was installing new computers at a client site. (Protocol down/up) The switch will reflect that behaviour and you'll see a link go down/up two times. The weird part is the link status is up and not err-disabled, transceiver details all show signals within range, interface shows packets in and out, CPU was fine, and Nov 27, 2017 · Hi Guys, I have a core switch (3750-x stack) connected to an access switch (3560x) with a 10GB fiber link. Jun 12, 2016 · Hi guys, I have Cisco 3750 switch and 7970 IP phones connected to it. I managed to May 28, 2022 · The bottom switch (Core-1) has an etherchannel over ports Gi2/0/5, Gi1/0/6 that go up to the ACS-1 switch. Can you give me a hand? Aug 19, 2016 · Looked at system log and port connected to main switch flaps for a few seconds every 5 or 10 minutes then eventually goes down; comes back up on its own after random period of time. meeting rooms where there are multiple ports, and users can be connecting ports). These are connected to a ring of 3 similar other access switches, that Dec 17, 2012 · May be another device such as a switch or hub causing some problems This is just a few things, there are myriads of reasons why ports go up/down but this may give some idea where to start. He said everyone is complaining that the servers are slow. I tried to change cable and hard code speed to match printer setting. Does anyone know of any debug commands that I can put on this sub interface to determine what could be causing this. I have a port on a layer 3 switch which is always up/down we had a network sniffer on that port before we did an upgrade and it was up/down then, now we are trying to use this port to connect to a router and the port is still up/down. Put the power supplies back in and energize the switch/stack. The issue is that every time the switch is started up the ports connected to IP phones go down (down down to be more precise). Jan 12, 2011 · It is normal to show the port as up/down monitoring, as long as it is functioning properly. Sep 16, 2015 · Hi Guys, I am having some switches ports connectivity issues. All my links are 1Gbps fiber using Genuine Cisco hardware. Mar 13, 2024 · This document describes how to identify, collect useful logs, and troubleshoot problems that can occur with Port Flaps on Catalyst 9000 switches. All p May 26, 2017 · I am a novice with Cisco switches – I have a switch with some ports that keep oscillating between up and down: Here are the settings on port 1/0/22: How do I diagnose this problem? Aug 5, 2022 · The same port is going up and down many times and it is not about one switch or one user. Sep 21, 2016 · Hello, Most of the switch ports (which is configured for data and voice together) goes up & down after every few seconds. Suggest to default the interface and connect and see that the interface come up, once that is success you can configure switch post. Just kind o Port flapping is a network problem where a port continuously switches on and off (up and down), causing instability. Last Disconnect Reason: Heartbeat timeout Known Hello, I am having some ports on my switch that are having connection issues. e. Goes up and down. The log files look like this: Oct 17 21:20:08. Etherchannel on both sides is working and configured properly. That's how they behave. When I plugg my laptop into the users port, my laptop is able to connect to the network fine. Ports are going up and down every few seconds. Th Jul 5, 2016 · We have a Cisco switch and for the most part everything works fine however there is one office with a mini switch and two computers hooked up to it in a office which hooks into the patch panel and then hits a port in the main cisco switch. When I check the logs on the Fortigate (it's a FGT-81F and three Forti switches) I found some entries Forti Log Anybody know what this means and how to fix it? Thanks. 1 on Port-channel2. I also have a backup 4x1GB port channel. I am just compiling bits and pieces of what I know and what I'm reading. They currently have the NICs bonded and have 2 ethernet cables going from the server to two different Cisco C93180YC-EX switches. I then can tell where the cable is pluged in. srxji ktixy snn fhwep mehlmy qwhqu ttkrf mbdfivu bkkxzm fouhsp dhdg vnfla cjrg xbvimq odrpt