• Creator
  • #2150541

    Cisco 800 series issue


    by jason.sincock ·

    Hi all,

    I have an issue with an 800 series router.
    We are using it as a backup connection for our email.
    When I created a nat for the emails to come through, normal emails
    would come through fine but any emails with an attachment on it
    would be blocked.
    In theory it should work because it still has the normal connection to
    use and the cisco’s connection as backup.
    I am wondering if there is a setting that limits the size of traffic
    coming through?
    Your help is greatly appreciated.

All Answers

  • Author
    • #2926328


      by jason.sincock ·

      In reply to Cisco 800 series issue


    • #2926311

      Yes and no

      by fregeus ·

      In reply to Cisco 800 series issue

      Yes there are commands that will limit the traffic going through your router. But no, that command will only restrict the flow of traffic, not the quantity. To your email would get through, just slower. Your cause is somewhere else.


      • #2926309

        Further help

        by jason.sincock ·

        In reply to Yes and no

        Any idea where that cause is?

        • #2926294


          by fregeus ·

          In reply to Further help

          I can tell you that i doubt very much that the network is the culprit. My guess (from experience) would be possibly an antivirus, antispam or firewall system that withholds the attachments for some reason. specially if the mail itself, without the attachement, gets to the destination.

          So I would do a thorough investigation of all step needed for mail to get in and see which system has the ability to withhold part of the message (ie the attachement).


    • #2926271


      by jellimonsta ·

      In reply to Cisco 800 series issue

      Do you have NBAR enabled on your ISR 800 router?
      Or do you have CBAC rules that are inspecting Email and attachments on the router?

      • #2925629

        Still denying attachments

        by jason.sincock ·

        In reply to NBAR

        I checked this and the IOS on the router doesn’t have NBAR.
        I checked CBAC rules and none are configured.

        • #2917312

          Issue found

          by jason.sincock ·

          In reply to Still denying attachments

          For those who are interested,
          we changed the router with a modem and found the issue
          still there so it looks like a problem with the mtu of the line.

          Thanks for the help

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