
I noticed on a couple of our mail servers, delivery to gmail was getting stuck in the outbound queue. Our MTAs are all sendmail If I hardcode delivery to gmail to 74.125.142.26 via a mailertable entry, mail goes through fine But if let it naturally select the inet6 addr, it hangs Running /var/spool/mqueue/rBLDcRmZ092661 (sequence 1 of 1) <miketancsa@gmail.com>... Connecting to gmail-smtp-in.l.google.com. via esmtp... 220 mx.google.com ESMTP v3si9282987qat.181 - gsmtp
EHLO smarthost2.sentex.ca 250-mx.google.com at your service, [2607:f3e0:80:80::2] 250-SIZE 35882577 250-8BITMIME 250-STARTTLS 250-ENHANCEDSTATUSCODES 250-PIPELINING 250 CHUNKING STARTTLS 220 2.0.0 Ready to start TLS
The addr is of course reachable. I check the routing and the AS seems legit. The path is 6939 15169 traceroute6 to 2607:f8b0:400d:c02::1a (2607:f8b0:400d:c02::1a) from 2607:f3e0:80:80::2, 64 hops max, 12 byte packets 1 2607:f3e0:80:80::1 0.585 ms 2 toronto-torix-6 0.478 ms 3 gw-he.ip6.torontointernetxchange.net 0.995 ms 4 2001:478:245:1::6 1.104 ms 5 2001:4860::1:0:28 1.684 ms 6 2001:4860::8:0:4398 15.514 ms 7 2001:4860::8:0:6375 21.308 ms 8 2001:4860::8:0:5e9d 37.368 ms 9 2001:4860::2:0:3568 28.932 ms 10 * 11 * 12 * 13 qe-in-x1a.1e100.net 28.663 ms I am coming from 2607:f3e0:80:80::2 in the above case tcpdump doesnt show anything obvious and since the payload is not readble I cant see it. I wonder if there is a way to get sendmail to print out the contents... -- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/

Of course, 2 min after sending this the problem goes away and mail flows once again :( ---Mike On 12/21/2013 8:56 AM, Mike Tancsa wrote:
I noticed on a couple of our mail servers, delivery to gmail was getting stuck in the outbound queue. Our MTAs are all sendmail
If I hardcode delivery to gmail to 74.125.142.26 via a mailertable entry, mail goes through fine
But if let it naturally select the inet6 addr, it hangs
Running /var/spool/mqueue/rBLDcRmZ092661 (sequence 1 of 1) <miketancsa@gmail.com>... Connecting to gmail-smtp-in.l.google.com. via esmtp... 220 mx.google.com ESMTP v3si9282987qat.181 - gsmtp
EHLO smarthost2.sentex.ca 250-mx.google.com at your service, [2607:f3e0:80:80::2] 250-SIZE 35882577 250-8BITMIME 250-STARTTLS 250-ENHANCEDSTATUSCODES 250-PIPELINING 250 CHUNKING STARTTLS 220 2.0.0 Ready to start TLS
The addr is of course reachable. I check the routing and the AS seems legit. The path is 6939 15169
traceroute6 to 2607:f8b0:400d:c02::1a (2607:f8b0:400d:c02::1a) from 2607:f3e0:80:80::2, 64 hops max, 12 byte packets 1 2607:f3e0:80:80::1 0.585 ms 2 toronto-torix-6 0.478 ms 3 gw-he.ip6.torontointernetxchange.net 0.995 ms 4 2001:478:245:1::6 1.104 ms 5 2001:4860::1:0:28 1.684 ms 6 2001:4860::8:0:4398 15.514 ms 7 2001:4860::8:0:6375 21.308 ms 8 2001:4860::8:0:5e9d 37.368 ms 9 2001:4860::2:0:3568 28.932 ms 10 * 11 * 12 * 13 qe-in-x1a.1e100.net 28.663 ms
I am coming from 2607:f3e0:80:80::2 in the above case
tcpdump doesnt show anything obvious and since the payload is not readble I cant see it. I wonder if there is a way to get sendmail to print out the contents...
-- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/

For the archives, I should have know this, but to get sendmail to spit out a little more of the exchange, a -d17 would have done the trick. eg sendmail -q -qRdestuser@gmail.com -v -d17 ---Mike On 12/21/2013 9:01 AM, Mike Tancsa wrote:
Of course, 2 min after sending this the problem goes away and mail flows once again :(
---Mike
On 12/21/2013 8:56 AM, Mike Tancsa wrote:
I noticed on a couple of our mail servers, delivery to gmail was getting stuck in the outbound queue. Our MTAs are all sendmail
If I hardcode delivery to gmail to 74.125.142.26 via a mailertable entry, mail goes through fine
But if let it naturally select the inet6 addr, it hangs
Running /var/spool/mqueue/rBLDcRmZ092661 (sequence 1 of 1) <miketancsa@gmail.com>... Connecting to gmail-smtp-in.l.google.com. via esmtp... 220 mx.google.com ESMTP v3si9282987qat.181 - gsmtp
EHLO smarthost2.sentex.ca 250-mx.google.com at your service, [2607:f3e0:80:80::2] 250-SIZE 35882577 250-8BITMIME 250-STARTTLS 250-ENHANCEDSTATUSCODES 250-PIPELINING 250 CHUNKING STARTTLS 220 2.0.0 Ready to start TLS
The addr is of course reachable. I check the routing and the AS seems legit. The path is 6939 15169
traceroute6 to 2607:f8b0:400d:c02::1a (2607:f8b0:400d:c02::1a) from 2607:f3e0:80:80::2, 64 hops max, 12 byte packets 1 2607:f3e0:80:80::1 0.585 ms 2 toronto-torix-6 0.478 ms 3 gw-he.ip6.torontointernetxchange.net 0.995 ms 4 2001:478:245:1::6 1.104 ms 5 2001:4860::1:0:28 1.684 ms 6 2001:4860::8:0:4398 15.514 ms 7 2001:4860::8:0:6375 21.308 ms 8 2001:4860::8:0:5e9d 37.368 ms 9 2001:4860::2:0:3568 28.932 ms 10 * 11 * 12 * 13 qe-in-x1a.1e100.net 28.663 ms
I am coming from 2607:f3e0:80:80::2 in the above case
tcpdump doesnt show anything obvious and since the payload is not readble I cant see it. I wonder if there is a way to get sendmail to print out the contents...
-- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/
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Mike Tancsa