From: "Dobbins, Roland" <rdobbins@arbor.net> Date: Fri, 3 Sep 2010 21:07:49 +0000
On Sep 3, 2010, at 8:02 PM, Patrick W. Gilmore wrote:
Could you point to more than one instance? I've not yet found one.
I've yet to run across this, either, FWIW, except on extremely restrictive special-purpose endpoint networks. Doesn't mean that it doesn't happen, but it doesn't seem to be nearly as prevalent as TCP/25 blockage on general SP access networks.
Worst case I have seen was the visitors network at EBC at one of the nation's largest telephone and Internet transit providers. They seemed to block ALL outgoing ports except 80, 443, and 22. No VPN. No submission port. No IMAP. (Didn't try POP3.) I tunneled mail over ssh, but I can imagine that a lot of corporate types who meet there are rather annoyed that they can't access mail. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751