It's mostly just preventing IPv6 traffic for us that relies on
AS174, which is a problem because some of our users are dependent on
lPv6-only networks.
I saw reports yesterday that Cogent has fixed the problem, but AS174
continues to fail to route IPv6 traffic, even this morning.
> Cogent had two fiber cuts in Southern California yesterday. It greatly
> affected our San Diego datacenter, causing all our traffic to flow through
> our LAX datacenter.
>
> This increase in rate has caused Microsoft/Outlook servers to defer all mail
> flow (even to our customers who are o365 users):
>
>
> 2026-09-04T10:28:53+00:00 003.mia postfix-relaycust/smtp[888736]:
> 4hbt2K63Nxxxxx: to=<xxxx>,
> relay=xxxx-com.mail.protection.outlook.com[52.101.10.16]:25, delay=77,
> delays=70/0.13/5.8/0.68, dsn=4.7.500,
> status=deferred (host xxx-com.mail.protection.outlook.com[52.101.10.16]
> said: 451 4.7.500 Server busy. Please try
> again later from [199.89.3.6]. (S77714)
> [BN2PEPF000055E1.namprd21.prod.outlook.com 2026-09-04T10:28:53.346Z
> 08DF0900FB158D96] (in reply to end of DATA command))
>
>
> Our San Diego center is back, but the flood of mail returning to it has
> caused the same issue.
>
> We're an email filtering service, not a bulk mailer of any type. We do
> selective outbound for regular business customers (not bulk, not
> transactional) - we just really need to relay inbound email to our customers
> and for their normal business outbound mail to get out.
>
> I've submitted a request via SNDS, but I don't know if a human will see it
> and intervene, and this is urgent for our customers.
>
> Can anyone put me in touch with a Microsoft contact who could possibly
> intervene?
>
> Thanks-
>
> Tom
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--
Postmaster - [email protected]
Randolf Richardson, CNA - [email protected]
Inter-Corporate Computer & Network Services, Inc.
Vancouver, Beautiful British Columbia, Canada
https://www.inter-corporate.com/
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