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Jan_Scholten
Jan_Scholten
New Member
August 6, 2012
Question

Strange OSPF Problem

  • August 6, 2012
  • 3 replies
  • 3124 views
I have setup a IPSec VPN to two central FGT (like in every other department) This is the only department running 4.3 at the moment (4.3.8) I have created two Interface based VPNs, which are up and running. No OSPF Routes are transported thou. get router info ospf neighbor shows my central FGT as EXSTART. debugging shows following: id=36868 msg=" OSPF: RECV[DD]: From 192.168.10.8 via CNT-Dep-W1W1:10.10.10.44: MTU size is too large (1412)" I have tried to reduce the mtu on the physical interface where the Interface VPNS terminate to 1400 but still receive the same error. I noticed that with (this) MR3 the VPN Interfaces are no longer shown as Subinterface of the phsical interface? Any hints on what could be the source for that?

    3 replies

    rwpatterson
    rwpatterson
    New Member
    August 6, 2012
    Have you tried playing with the OSPF interface MTU? CLI only adjustment.
      config router ospf          config ospf-interface              edit " OSPF_Interface"                   set cost 10                  set interface " VPN.Interface"                   set ip xxx.xxx.xxx.xxx                  set mtu 1500                  set network-type point-to-point              next          end  end
    This works on at least V4, MR2, P 12.
    emnoc
    emnoc
    New Member
    August 6, 2012
    Yes the MTU ignore needs to be enable from either end. Also ensure your ospf parameters are the same ( hello and dead intervals )
    Jan_Scholten
    Jan_ScholtenAuthor
    New Member
    August 6, 2012
    SET MTU 1400 in the central site for just this two OSPF Interfaces sorted the problem. Thanks alot
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