[leafnode-list] Re: fetchmail, fetchnews can't get thru router

Matthias Andree matthias.andree at gmx.de
Tue Aug 5 11:23:40 CEST 2008


Christian Ebert <blacktrash at gmx.net> writes:

> Hello,
>
> I apologize in advance for this probably being off topic, and the
> cross-post, but I am desperate for some kind of help: pointers to
> docs etc.
>
> The problem:
>
> I changed my internet access at home from dsl to vdsl, and am now
> connected via a router (Speedport W 701v). Everything works fine
> except fetchmail and fetchnews -- they just hang. Even smtp (via
> msmtp) works, also ssh, jabber, irc (both also via ssl) etc.

What do you see in tcpdump or tshark for the respective connection while
it's still live?

Any tools or web pages of the Speedport WRT link/line quality or any
suspect logging in the Speedport's web interface?

Does your Speedport have current firmware?

Does your Apple have current kernel + network utilities?

Do you have some sort of firewall on the local (Apple) computer?

Do things start to work if you set your MTU of the computer's interface
leading to the router to, say, 1400? (Not sure what overhead VDSL
entails, if it's different from regular PPP over DSL.)

> As my provider is not exactly helpful to say the least, I am

Are they still shuffling calls for the same case between different call
centers with "I have do call XYZ to ask..." sort of replies as they used
to a year ago?

> The most annoying thing is that AppleMail *is* able to retrieve
> mail from all accounts; which led the hotline to say: well, use
> the standard mail program then ... of course there isn't any
> "standard program" to fetch news etc. etc. I refrain from
> ranting. This guy also said that this works for him with Linux,
> that it must be a Mac-Problem. But what kind of Mac-Problem?
> Nobody has any idea.

Broken Path MTU discovery through improper ICMP or TCP/IP flag filtering
is a more common problem, but...

> Here's also a log of an attempt that hung a tiny bit later in 1
> instance (passwords provided by .netrc):
>
> fetchmail: 6.3.9-rc2 querying milestone.prossl.de (protocol IMAP) at Sun, 03 Aug 2008 12:06:23 +0200 (CEST): poll started
> fetchmail: timeout after 60 seconds waiting to connect to server milestone.prossl.de.
> fetchmail: socket error while fetching from ***@milestone.prossl.de

...the fragments used to connect are not large enough to trigger path
MTU problems.

> $ leafnode-version
> version: leafnode-2.0.0.alpha20080624a
> current machine: Darwin krille.blacktrash.org 8.11.0 Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC Power Macintosh powerpc

Hm. No fetchnews log provided - but I'm not sure if that would be
any different from fetchmail's log (something like "server went away
while ..." is likely).

HTH

-- 
Matthias Andree



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