Hi Bill -
In message <Pine.LNX.3.96.980626133519.563B-100000@sparrow>, William
Stearns wr
ites:
>Good day, Joshua,
>
>On Fri, 26 Jun 1998, Joshua Heling wrote:
>
>> I have a persistent problem at a site that's masquerading a
5-node
>> LAN through a linux box running 2.0.34 with ppp 2.2.0f and an
>> external ISDN TA.
>> <...snip...>
>
> The problem is not in ip masquerading, I think. It's in pppd.
> Your pppd is asking the other end to reply with LCP (link control
>protocol) echoes; the lower level equivalent to ICMP pings. The
other end
>doesn't respond - this might be a protocol violation, but that's
not the
>real issue.
> The way around it is to tell your end to stop asking for lcp
>echoes. From "man ppp":
>
I see what you're getting at, but the reason I put the
lcp-echo-(interval,failure) lines in /etc/ppp/options in the first
place was that the connection was dropping. I suspected that it was
dying, but the ppp0 interface remained up, so I added the lcp
options to allow me to see what was happening.
Interestingly, the other side *does* reply to the first few minutes
of lcp echo requests. It is quite clear in the logs when pppd's
debug option is set - my side issues "LCP EchoReq" and the other
side faithfully responds with "LCP EchoRepl" - until it just stops.
I agree that this -shouldn't- be a masquerading issue, but I've been
unable to get the EchoRepl's to stop coming unless I use of the
inside machines through the masquerade (after which it happens
within a few minutes). It is this correlation that has caused me to
start looking at the possibility of a masq/forwarding interaction
... I don't know what else to hypothesize...
When lcp-echo is off, the connection just dies silently around the
same time it does when lcp-echo is on... ;(
Thanks for the suggestion,
Joshua
> lcp-echo-failure n
> If this option is given, pppd will presume the peer
> to be dead if n LCP echo-requests are sent without
> receiving a valid LCP echo-reply. If this happens,
> pppd will terminate the connection. Use of this
> option requires a non-zero value for the lcp-echo-
> interval parameter. This option can be used to
> enable pppd to terminate after the physical connec-
> tion has been broken (e.g., the modem has hung up)
> in situations where no hardware modem control lines
> are available.
>
> lcp-echo-interval n
> If this option is given, pppd will send an LCP
> echo-request frame to the peer every n seconds.
> Normally the peer should respond to the echo-
> request by sending an echo-reply. This option can
> be used with the lcp-echo-failure option to detect
> that the peer is no longer connected.
>
>
> I suspect that putting the following lines into /etc/ppp/options
>will stop your problem:
>
>lcp-echo-failure 0
>lcp-echo-interval 0
>
> Best of luck. Cheers,
> - Bill
>
>--------------------------------------------------------------------
-------
>Unix _is_ user friendly. It's just very selective about who its
friends
>are. And sometimes even best friends have fights.
>William Stearns ([EMAIL PROTECTED])
>--------------------------------------------------------------------
-------
>
>
--------
Joshua Heling [EMAIL PROTECTED]
SecurePipe Communications, Inc.
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