Fails to learn mac address on Fiber interface with ISP

Hi,
We have a problem to bring a new 3750 switch interface up with the ISP.
Current interface configuration on the router 7500 with SC/Single mode 1000 Base LX is
interface GigabitEthernet4/0/0
description ###### ISP #######
ip address 1.1.1.2 255.255.255.252
no ip redirects
no ip unreachables
load-interval 30
no negotiation auto
no cdp enable
end
works perfectly fine.
we are trying to move this link to a Cisco 3750G on SFP single mode 1000 baase LX with the same configuration as below
interface GigabitEthernet1/0/51
no switchport
ip address 1.1.1.2 255.255.255.252
load-interval 30
no ip redirects
no ip unreachables
no cdp enable
speed nonegotiate
we dont get any errors on the link but it fails to learn the mac address from the isp.
checked the following.
1. tried changing the SFP and the fiber.
2. checked internally connecting back to back with another cisco device - works fine .
3. checked with the isp for any static arp on their side and it is a no.
I am wondering why it fails to learn the mac-address when it can self ping its own ip address and also the layer stays up with no errors on both the sides.
Thanks

Doesn't feel like a fiber/optical issue but a configuration mismatch on one of the end devices.

Similar Messages

  • SNMP How to get number of learned MAC addresses on Switch interface

    There is nice c2900PortNumberOfLearnedAddresses table in C2900-MIB, but it's outdated and not supported by modern switches.
    Is there similar table for modern switches? Most interested in Catalyst 2960 and 3750.
    Fetching whole forwarding table is not a good idea.

    Following guide should help you with this:
    http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094a9b.shtml
    http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a00801c9199.shtml
    -Thanks

  • Switch learning mac addresses

    In a video that I watched a few days ago someone explained a basic process of booting up a switch and how a switch learns mac addresses. He said something that I would like to discuss. I know... it is not important but want to clarify :)
    PC1---SW1----PC2
    PC1 wants to send sth to PC2. In the video it was said:
    'a frame arrives at SW1 and SW1 learns the mac address of pc1 but it does not know the mac address of pc2 so it will flood this frame to all ports'
    My uderstanding is that it all starts with an arp message: pc1 does not know the mac address and sends an arp and it will allow the switch to learn both mac addresses: pc1 and pc2. I am too lazy to do it in wireshark but did that in PT and that's what I saw as well. After the arp - switch learnt both macs and did not flood the frame.
    Am I correct? I know it is not important but... ;-)

    It may be possible that there was some aspect of the switch environment in the video that would change the behavior (perhaps something like a long timer for the ARP cache in the PC and a short MAC ageing timer on the switch). But in general you are correct. PC1 would send an ARP request as a broadcast, the switch would learn the MAC of PC1 and forward the ARP request. When PC2 sends its response to the ARP request the switch would learn the MAC of PC2 and forward the ARP response. So the switch should have both MAC addresses when data traffic begins to flow.
    HTH
    Rick

  • "failed to get MAC address for machine"

    here is the jist of things.
    installed leopard and have it pimped out to my personal specs. I like where everything is and how things are working. No issues. just so you know, i only use WIFI for internet, i share with the guys upstairs. In order to get wifi on my machine, i use a USB dongle. works great no issues with it ever, well until i physically broke it. No big deal. So i replaced it with another one, different drivers/chipset worked.. And since i installed leopard i only backed it up once with TM, i dont care for daily/hrly backups, weekly is fine for me. Now after 2 weeks and a new usb network card. TM gives me an error. i click on the little red i and it says "the backup volume could not be found" so googled and searched the forums not much help, so i tried and formated my ext drive repaired and click on TM again, same error. In the error log in console, right after i turn on TM i get this error, "failed to get MAC address for machine" then 180 secs later, TM fails. again, and again.
    Can anyone tell me where i can find what MAC address its looking for??? ethernet has never been plugged in to my machine ever. its only been online via USB wifi. Im really lost here, i dont know what i can do.. im sure if i try another drive ill get the same error. please help if you can.. much appriciated.
    Jamie

    yeah i get a 'failed to get mac address' message too. what's weird is that it seems that leopard 'broke' my ethernet (there was no mac address, couldn't connect to the internet through ethernet after a clean install), and then 10.5.2 'fixed' it. for some reason, i have an 'ethernet 2' heading in system preferences that works correctly and has a mac address and everything, while the regular 'ethernet' tab doesn't work at all. however, i still get this time machine error. i don't understand why time machine is so incredibly fickle. sorry, i'm really of no help to anyone, other than adding another voice to the frustration.

  • What's the purpose when we config ipv6 address for an interface with 128bit mask

    What's the purpose when we config ipv6 address for an interface with 128bit mask?
    Thanks

    If you configure a loopback-interface you can use a /128 there.
    "Normal" interfaces should always use /64 (RFC 4291) while on router-to-router-links you can use a /127 (RFC 6164).
    Don't stop after you've improved your network! Improve the world by lending money to the working poor:
    http://www.kiva.org/invitedby/karsteni

  • Can't clear mac address table from interface

    hello all.
    I'm facing a problem, and i've also tried to workaround but not sucessfully.
    I've got a polycom phone on the swich. When I connect a laptop on that port, the mac address is learned by the switch and keep the mac address even if I disconnect the ethernet cable from that port and if I try to connect the same laptop on other port on the same switch I've got errdisable error in the last connected port. Although I was figuring out what's wrong and seems that the mac address is kept for some reason in the first port.
    sw02#show mac address-table interface f0/19
              Mac Address Table
    Vlan    Mac Address       Type        Ports
     60   3c07.5417.9069   STATIC      Fa0/19 
     80    0004.f21e.afa7    STATIC      Fa0/19 
    this is a 2960, Version 12.2(44r)SE4
    with a Polycom SoundPoint IP 330 connected on vlan 80
    I was searching to clear the mac address table on that interface but the IOS version didn't give me the static option
    sw02#clear mac address-table ?
      dynamic       dynamic entry type
      move          move keyword
      notification  Clear MAC notification Global Counters
    As there's no dynamic entries on that interface the mac addresses remain on the f0/19 interface.
    I've tried with other switches and with other laptops and is the same errdisable status.
    sw02#show run int f0/19
    interface FastEthernet0/19
     description VoIP
     switchport access vlan 60
     switchport mode access
     switchport nonegotiate
     switchport voice vlan 80
     switchport port-security maximum 5
     switchport port-security
     no snmp trap link-status
     ip dhcp snooping limit rate 100
    end
    any thought?

    the mac addresses are not manually configured.
    yes, that's my point. when I disconnect the ethernet cable the mac addresses are not flushed from the mac table.
    Although I don't understand why the mac addresses are kept in the interface, if I force the interface aging time to 1 min, the problem don't occur anymore.
    I was reviewing the switch config and I've got ports with aging time 0 (that learn and flush the mac addresses dynamically) and I've got ports with aging time 1 (that learn and flush the mac addresses at the end of 60 seconds)
    The problem is solved although I need to investigate this issue in other switch models and with other voip phones.
    Tks Jon and Julio

  • MAC addresses of redundant interfaces on failover pair of CSS.

    Helo all, I wanted to know what happens to the MAC addresses of the failover interfaces on the two CSS devices configured as a failover pair when a failover occurs?
    Also what happens in a failover event in general? Can anyone point me to some documents describing the failover process.
    Thank you,
    Dmitry.

    Hi Dimitry,
    Here is the URL for the configuration for the Configuring VIP and Virtual IP Interface Redundancy follow the configuration guide which may help you
    http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/css11500series/v8.20_v8.10/configuration/redundancy/guide/VIPRedun.html
    http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/css11500series/v8.20_v8.10/configuration/redundancy/guide/ASR.html
    Configuring Box to box redundancy:
    http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/css11500series/v8.20_v8.10/configuration/redundancy/guide/Redndncy.html
    CSS 11500 Active-Active Stateful Failover ASR in One-Armed Mode Configuration Example
    http://www.cisco.com/en/US/products/hw/contnetw/ps792/products_configuration_example09186a00802206a3.shtml
    Box-to-Box Redundancy on the CSS 11xxx Configuration Example - Ciscowiki
    http://supportwiki.cisco.com/ViewWiki/index.php/Box-to-Box_Redundancy_on_the_CSS_11xxx_Configuration_Example
    Kindly find full range of configuration examples on CSS here :
    Cisco CSS 11500 Series Content Services Switches
    Configuration Examples and TechNotes
    http://www.cisco.com/en/US/products/hw/contnetw/ps792/prod_configuration_examples_list.html
    Cisco CSS 11500 Series Content Services Switches
    http://supportwiki.cisco.com/ViewWiki/index.php/Category:Cisco_CSS_11500_Series_Content_Services_Switches
    Kindly see URL given below for my other articles
    http://boardreader.com/fp/Cisco_Systems_Networking_Profe_309110/Application_Networking_543840.html#hot_threads
    If possible plz rate sothat I can be helpful to other people also as it will enhance my credibility.
    Sachinga.hcl

  • How to trace MAC  Address Of a Machine with PL/SQL

    As MAC Address Of a Machine is Unique, for security, how to use trace the MAC Address of a machine on a WAN/LAN and record it in the database.Please note that it is important part of Audit Trail

    MAC ADDRESS is unique, whereas IP Address is variable. Experienced user can very easily change (fake) MAC address.
    Maybe you will be surprised it is trivial as changing of IP.
    You may be able to build a component that is external to the database that can determine a MACOn linux (for example) you could use "arping" command or retrive MAC adressess from arp cache using "arp" command. arp cache stores MAC adresess of all computers which are or was connected to machine. These commands can run only privileged user (root) but you could give execute privilege for specific user (oracle) via "sudo". You can execute this commands using external procedure or call it from Java stored procedure.
    It think tracking of IP will be enough beause IP must be unique on network (or in specific subnet).
    So MAC tracking is waste of time (IMHO).

  • I use to have to buy something to have my dot mac address do I still with iCloud?

    I use to have to buy something to have my dot mac address. Do I still with iCloud? I still  use my .m

    thanks so much for your time and effort
    I know it does work...I use to have to buy the mobileme...now it seems iCloud is free?
    Thank you

  • Cisco CSR 1000V - BDI learning mac address

    Hello all,
    about BDI, I know it is not supported through OTV. DDTS CSCuj59314 has been logged to track support of BDI over OTV. Anyone know if this problem is resolved?
    Thanks in advance
    Roberto Loiudice

    Hello,
    no one else has encountered the same problem?
    In general, someone has managed to run correctly csr1000v as SSL VPN terminator on Amazon environment ?
    Any example / network schema / suggestion?
    Thanks in advance for any replies.
    Paolo

  • CS 5.5 on a Mac running Parallels to interface with a windows system.

    Hi
    I have just upgraded to CS5.5 and amongst many other things I cannot seem to copy & paste into InDesign 5.5 from my Windows apps. Can anyone shed any light please?
    Cheers

    Sounds like a Parallels issue. Why don't you ask on their website.

  • MAC address learning

    On various switches I have devices connected to, some of the ports never seem to learn the mac-address of the connected device. Anyone have an explanation or fix for why this randomly happens?

    Hi Friend,
    The switch will not learn a mac address till the time device connected to it send some request out from its source mac address.
    Like a workstation if you connect to it and your pc is in hut state the switch will not learn a mac address.
    Incase you power your pc up it will sned a broadcats ofr arp entry and that time switch will learn a mac address because now pc has send some request with its mac address.
    So just check which all devices connected to the switch for which it does not learn mac address are those devices active and up in the network.
    HTH, if yes please rate the post.
    Ankur

  • EEM for learned MAC

                       Hi there,
    Is there any easy way to create an EEM script so if one any switch interface learned MAC address reached to 4 then it will send an email as alert.
    Any idea? i am trying to work out but cant find any basic EER script any where.
    Thanks

    See this thread:
    https://supportforums.cisco.com/thread/2169067?tstart=0
    The script there looks at the DHCP pool, but it could be easily modified to look at "show mac address-table" for each port instead.  For each port, if the number of lines in the output exceeds your threshold, send an email for that port.

  • FWSM - Duplicated MAC Addresses across contexts

    I have two 7609S routers each with a FWSM running 4.0( 8)
    I am licensed for 20 contexts.
    Recently, I added a context for a new application and required access to a VLAN that already had an interface in another context.
    The MAC address assigned to the interface in the new context was assigned the same MAC address as the interface in the previous context.
    This caused an application running through the first context to fail.
    I know that on the FWSM I cannot hardcode a MAC address to an interface in a context so how do I get around this problem caused by the duplicate MAC addresses?
    Thanks, Ted

    Hi Ted,
    The short answer is that you'll need to add static NAT statements (identity NAT is fine) to both contexts for each of the destinations that live behind each context.
    For example, assume you share the outside interface across both of the following contexts:
    ContextA - protects hosts in the 10.1.1.0/24 inside subnet
    ContextB - protects hosts in the 10.2.2.0/24 inside subnet
    You would need to add the following statics:
    ContextA:
    static (inside,outside) 10.1.1.0 10.1.1.0 netmask 255.255.255.0
    ContextB:
    static (inside,outside) 10.2.2.0 10.2.2.0 netmask 255.255.255.0
    See the following guide for more details:
    http://www.cisco.com/en/US/docs/security/fwsm/fwsm40/configuration/guide/contxt_f.html#wp1124236
    -Mike

  • Format of WCS template file for mac-address filtering

    I am looking for the format of the template file used for WCS Mac-address filtering.
    I need to know how the fields are delimited within the file.

    Sample csv file :
    #MAC Address,Profile Name,Interface,Description
    22:22:22:22:22:22,profile8,management,cisco
    00:00:00:00:00:01,myprofile,int1,First filter
    00:00:00:00:00:02,,management,Second filter
    00:00:00:00:00:03,,,Third filter
    Note: "MAC Address" and "Description" are mandatory fields

Maybe you are looking for