Re: ssh & select() problem on 5.3

From: Claudiu Dragalia-Paraipan (dr.clau_at_gmail.com)
Date: 11/29/04

  • Next message: Julian Elischer: "Re: top under 5.3-RELEASE" 
    Date: Mon, 29 Nov 2004 23:09:54 +0200
To: current@freebsd.org

    Peter Jeremy wrote:
    > On Sun, 2004-Nov-28 18:43:47 +0200, Claudiu Dragalia-Paraipan wrote:
    >
    >>Since the problem occurs only when I connect to the firewall or to a
    >>server behind it, I started to suspect a hardware failure. Could a
    >>network card cause such problems ?
    >
    >
    > A couple of people have mentioned path-MTU problems. I've also bumped
    > into this problem when playing with VLANs where one end of the VLAN
    > trunk doesn't support long frames - an oversize packet will get ignored
    > by the receiver without any error being returned.
    >

    It seems that packets of size more then 1478 are dropped somewhere, but
    not on the FreeBSD Firewall. The problem seems to be that it never
    receives a ICMP "fragmentation needed but DF set".
    Unfortunately I have control only over the firewall and what's behind it.
    Next after the firewall (towards internet) there are a switch and a
    Cisco router. I asked about the settings of this two, and it seems that
    the switch is used for VLANs, and the Cisco for making a tunnel over
    fiber channel with the next hop.
    I have too few information about this at the moment, but I am almost
    certain that the problems are occuring because of the Cisco router.
    I did a traceroute from the firewall to outside, and big packets always
    stop on Cisco router.
    A traceroute from outside to the firewall always stops at the hop
    exactly before the cisco router I am talking about, which I suppose is
    the other end of this tunnel. 

    -- 
Claudiu Dragalina-Paraipan
dr.clau@gmail.com

  • Next message: Julian Elischer: "Re: top under 5.3-RELEASE"

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