[Bug 1805027] Re: systemd-resolved can't resolve Comcast mail server addresses
Ubfan
1805027 at bugs.launchpad.net
Thu Dec 20 23:26:18 UTC 2018
Tried the developers/proposed checkoff, but the 239systemd.. package is still not available. In any case, Ubuntu 18.04 has problems connecting with smtp.comcast.net (through evolution, recommended port 587).
The error trying to send an email is:
An error occurred while sending, how do you want to proceed...
"The reported error was "Could not connect to smtp.comcast.net: Network is unreadable".
But of course it is, ping and dig both work (see below).
Note that unlike the pop3, imap, (and mail) .comcast.net names, smtp DNS lookup results are small,
one CNAME and one A , so bug 1804487 probably does not apply.
$ ping smtp.comcast.net
PING smtp.g.comcast.net (96.114.157.81) 56(84) bytes of data.
64 bytes from omta-po.sys.comcast.net (96.114.157.81): icmp_seq=1 ttl=56 time=39.3 ms
64 bytes from omta-po.sys.comcast.net (96.114.157.81): icmp_seq=2 ttl=56 time=40.6 ms
$ dig smtp.comcast.net
; <<>> DiG 9.11.3-1ubuntu1.3-Ubuntu <<>> smtp.comcast.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39553
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;smtp.comcast.net. IN A
;; ANSWER SECTION:
smtp.comcast.net. 3185 IN CNAME smtp.g.comcast.net.
smtp.g.comcast.net. 18 IN A 96.114.157.81
;; Query time: 14 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Thu Dec 20 15:00:52 PST 2018
;; MSG SIZE rcvd: 82
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https://bugs.launchpad.net/bugs/1805027
Title:
systemd-resolved can't resolve Comcast mail server addresses
Status in systemd package in Ubuntu:
Triaged
Bug description:
1) Ubuntu release: 18.10
2) systemd-resolved version: (Default latest version that comes with Ubuntu 18.10)
3) Expected behavior: Comcast's POP3 mail server addresses to be resolved to IP addresses
4) Actual behavior: Comcast's POP3 mail server addresses can't be resolved to IP addresses
Starting on Monday, November 19, 2018, Comcast made a DNS change
related to its POP3 mail servers (mail.comcast.net and
pop3.comcast.net) that prevent resolved from being able to resolve
those domains into IP addresses. When I try to ping either host
(mail.comcast.net or pop2.comcast.net), I get this error:
tom at deathstar:~$ ping mail.comcast.net
ping: mail.comcast.net: Name or service not known
tom at deathstar:~$
When I manually lookup up the domain, I get these results:
tom at deathstar:~$ nslookup mail.comcast.net
Server: 127.0.0.53
Address: 127.0.0.53#53
Non-authoritative answer:
mail.comcast.net canonical name = imap.ge.xfinity.com.
Name: imap.ge.xfinity.com
Address: 96.118.242.209
Name: imap.ge.xfinity.com
Address: 96.118.242.197
Name: imap.ge.xfinity.com
Address: 96.118.242.233
Name: imap.ge.xfinity.com
Address: 96.118.242.225
Name: imap.ge.xfinity.com
Address: 96.118.242.226
Name: imap.ge.xfinity.com
Address: 96.118.242.217
Name: imap.ge.xfinity.com
Address: 96.118.242.208
Name: imap.ge.xfinity.com
Address: 96.118.242.230
Name: imap.ge.xfinity.com
Address: 96.118.242.232
Name: imap.ge.xfinity.com
Address: 96.118.242.218
Name: imap.ge.xfinity.com
Address: 96.118.242.211
Name: imap.ge.xfinity.com
Address: 96.118.242.242
Name: imap.ge.xfinity.com
Address: 96.118.242.221
Name: imap.ge.xfinity.com
Address: 96.118.242.196
Name: imap.ge.xfinity.com
Address: 96.118.208.40
Name: imap.ge.xfinity.com
Address: 96.118.208.99
Name: imap.ge.xfinity.com
Address: 2001:558:fc11:9:f816:3eff:fee8:4f07
Name: imap.ge.xfinity.com
Address: 2001:558:fc11:9:f816:3eff:fe7d:1b0c
Name: imap.ge.xfinity.com
Address: 2001:558:fc11:9:f816:3eff:fe25:5ae5
Name: imap.ge.xfinity.com
Address: 2001:558:fc11:9:f816:3eff:fef6:babc
Name: imap.ge.xfinity.com
Address: 2001:558:fc11:9:f816:3eff:fe87:c172
Name: imap.ge.xfinity.com
Address: 2001:558:fc11:9:f816:3eff:fee6:7a57
Name: imap.ge.xfinity.com
Address: 2001:558:fc11:9:f816:3eff:fe0f:a4a
Name: imap.ge.xfinity.com
Address: 2001:558:fc11:2:f816:3eff:fec7:cb93
Name: imap.ge.xfinity.com
Address: 2001:558:fee2:1000:f816:3eff:fe42:4f14
Name: imap.ge.xfinity.com
Address: 2001:558:fc18:0:f816:3eff:fe33:9aaa
Name: imap.ge.xfinity.com
Address: 2001:558:fc18:0:f816:3eff:feb2:8c0d
Name: imap.ge.xfinity.com
Address: 2001:558:fc18:0:f816:3eff:fef1:25a5
Name: imap.ge.xfinity.com
Address: 2001:558:fc18:0:f816:3eff:febd:320a
Name: imap.ge.xfinity.com
Address: 2001:558:fc18:0:f816:3eff:fe36:aba3
Name: imap.ge.xfinity.com
Address: 2001:558:fc18:0:f816:3eff:fe3f:76f2
Name: imap.ge.xfinity.com
Address: 2001:558:fc18:0:f816:3eff:fe45:1d1e
tom at deathstar:~$ dig mail.comcast.net
; <<>> DiG 9.11.4-3ubuntu5-Ubuntu <<>> mail.comcast.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 15037
;; flags: qr rd ra; QUERY: 1, ANSWER: 17, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;mail.comcast.net. IN A
;; ANSWER SECTION:
mail.comcast.net. 15 IN CNAME imap.ge.xfinity.com.
imap.ge.xfinity.com. 12 IN A 96.117.3.119
imap.ge.xfinity.com. 12 IN A 96.117.3.96
imap.ge.xfinity.com. 12 IN A 96.117.3.143
imap.ge.xfinity.com. 12 IN A 96.117.3.145
imap.ge.xfinity.com. 12 IN A 96.117.3.129
imap.ge.xfinity.com. 12 IN A 96.117.3.148
imap.ge.xfinity.com. 12 IN A 96.117.3.201
imap.ge.xfinity.com. 12 IN A 96.117.3.136
imap.ge.xfinity.com. 12 IN A 96.118.133.238
imap.ge.xfinity.com. 12 IN A 96.117.3.128
imap.ge.xfinity.com. 12 IN A 96.117.3.144
imap.ge.xfinity.com. 12 IN A 96.117.2.238
imap.ge.xfinity.com. 12 IN A 96.117.3.110
imap.ge.xfinity.com. 12 IN A 96.117.3.140
imap.ge.xfinity.com. 12 IN A 96.117.3.154
imap.ge.xfinity.com. 12 IN A 96.117.3.132
;; Query time: 13 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Tue Nov 20 06:58:31 PST 2018
;; MSG SIZE rcvd: 334
tom at deathstar:~$
Before November 19, 2018, everything was working fine. The initial
indication there was a problem was Mozilla Thunderbird failed to
connect to Comcast's POP3 mail server. Once I did some investigation,
I found the information above.
I have since disabled system-resolved and have installed "Unbound".
After installing "Unbound", I'm able to ping "mail.comcast.net"
without issue and Mozilla Thunderbird can contact successfully
Comcast's POP3 mail servers.
I started a thread about this on Ubuntuforums.org:
https://ubuntuforums.org/showthread.php?t=2406399
and others report being impacted by this as well.
Let me know if more information is needed! Thanks!
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