comcast Too many sessions opened

Hello All,

I'm having an issue with Comcast. Can someone tell me how to narrow down what is going on and how to resolve it? (I replaced the valid e-mail address with X's, and the real domain with "". Thanks in Advance! - Sam

linode768-sr [3] sr> telnet 25

Trying 2001:558:fe21:2a::6…

Connected to

Escape character is '^]'.

421 comcast Too many sessions opened


/var/spool/mqueue (2 requests)

-----Q-ID----- --Size-- -----Q-Time----- ------------Sender/Recipient-----------

t3RERYSN020985 2271 Mon Apr 27 09:27 <>

(Deferred: 421 comcast Too ma)


t3RF6GPm002155 2495 Mon Apr 27 10:06 <>



Total requests: 2

3 Replies

Since you're connecting via IPv6, maybe you're running into this problem?

Thanks, I think this is separate. In the past I was getting the error "..found on one or more DNSBLs, see … p#BL000001"

But then I changed sendmail to use IPV4 address, and now getting the "Too many sessions opened" error message.

You might want to look at destination_concurrency settings: see … estination">


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