Jeff,
Following is the tcpdump on ppp0. Unfortunately, my tcpdump interpretive skills are a bit lacking. While I am researching, any feedback/hints you might be able to give that might help point us in the right direction would be greatly appreciated.
admin@mtcdt:~# tcpdump -i ppp0 -v
tcpdump: listening on ppp0, link-type LINUX_SLL (Linux cooked), capture size 65535 bytes
14:16:09.955606 IP (tos 0×0, ttl 64, id 38569, offset 0, flags [DF], proto UDP (17), length 75)
10.53.230.46.13489 > google-public-dns-a.google.com.domain: 41116+ A? VBIOTHUB001.azure-devices.net. (47)
14:16:09.955969 IP (tos 0×0, ttl 64, id 34618, offset 0, flags [DF], proto UDP (17), length 75)
10.53.230.46.13489 > google-public-dns-b.google.com.domain: 41116+ A? VBIOTHUB001.azure-devices.net. (47)
14:16:10.234860 IP (tos 0×58, ttl 56, id 52527, offset 0, flags [none], proto UDP (17), length 131)
google-public-dns-a.google.com.domain > 10.53.230.46.13489: 41116 2/0/0 VBIOTHUB001.azure-devices.net. CNAME ihsu-prod-by-002.cloudapp.net., ihsu-prod-by-002.cloudapp.net. A 104.40.49.44 (103)
14:16:10.235041 IP (tos 0×58, ttl 56, id 23505, offset 0, flags [none], proto UDP (17), length 131)
google-public-dns-b.google.com.domain > 10.53.230.46.13489: 41116 2/0/0 VBIOTHUB001.azure-devices.net. CNAME ihsu-prod-by-002.cloudapp.net., ihsu-prod-by-002.cloudapp.net. A 104.40.49.44 (103)
14:16:10.237000 IP (tos 0×0, ttl 64, id 47542, offset 0, flags [DF], proto TCP (6), length 60)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [S], cksum 0×4579 (correct), seq 2686456706, win 29200, options [mss 1460,sackOK,TS val 109108 ecr 0,nop,wscale 5], length 0
14:16:10.582955 IP (tos 0×0, ttl 64, id 38577, offset 0, flags [DF], proto UDP (17), length 71)
10.53.230.46.63275 > google-public-dns-a.google.com.domain: 5028+ PTR? 46.230.53.10.in-addr.arpa. (43)
14:16:10.707673 IP (tos 0×58, ttl 56, id 3608, offset 0, flags [none], proto UDP (17), length 71)
google-public-dns-a.google.com.domain > 10.53.230.46.63275: 5028 NXDomain 0/0/0 (43)
14:16:10.710373 IP (tos 0×58, ttl 108, id 10000, offset 0, flags [DF], proto TCP (6), length 60)
104.40.49.44.8883 > 10.53.230.46.34357: Flags [S.], cksum 0xb138 (correct), seq 221732293, ack 2686456707, win 8192, options [mss 1380,nop,wscale 8,sackOK,TS val 32995737 ecr 109108], length 0
14:16:10.710746 IP (tos 0×0, ttl 64, id 47543, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [.], cksum 0xfbf5 (correct), ack 1, win 913, options [nop,nop,TS val 109155 ecr 32995737], length 0
14:16:10.712627 IP (tos 0×0, ttl 64, id 47544, offset 0, flags [DF], proto TCP (6), length 221)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [P.], cksum 0x15ff (correct), seq 1:170, ack 1, win 913, options [nop,nop,TS val 109155 ecr 32995737], length 169
14:16:10.798944 IP (tos 0×58, ttl 108, id 10001, offset 0, flags [DF], proto TCP (6), length 1420)
104.40.49.44.8883 > 10.53.230.46.34357: Flags [.], cksum 0x12fa (correct), seq 1:1369, ack 170, win 513, options [nop,nop,TS val 32995745 ecr 109155], length 1368
14:16:10.799341 IP (tos 0×0, ttl 64, id 47545, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [.], cksum 0xf589 (correct), ack 1369, win 1003, options [nop,nop,TS val 109164 ecr 32995745], length 0
14:16:10.803928 IP (tos 0×58, ttl 108, id 10002, offset 0, flags [DF], proto TCP (6), length 1420)
104.40.49.44.8883 > 10.53.230.46.34357: Flags [.], cksum 0x2f5b (correct), seq 1369:2737, ack 170, win 513, options [nop,nop,TS val 32995745 ecr 109155], length 1368
14:16:10.804236 IP (tos 0×0, ttl 64, id 47546, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [.], cksum 0xefd5 (correct), ack 2737, win 1094, options [nop,nop,TS val 109165 ecr 32995745], length 0
14:16:10.804367 IP (tos 0×58, ttl 108, id 10003, offset 0, flags [DF], proto TCP (6), length 895)
104.40.49.44.8883 > 10.53.230.46.34357: Flags [P.], cksum 0×9887 (correct), seq 2737:3580, ack 170, win 513, options [nop,nop,TS val 32995745 ecr 109155], length 843
14:16:10.804715 IP (tos 0×0, ttl 64, id 47547, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [.], cksum 0xec35 (correct), ack 3580, win 1179, options [nop,nop,TS val 109165 ecr 32995745], length 0
14:16:10.924826 IP (tos 0×0, ttl 64, id 47548, offset 0, flags [DF], proto TCP (6), length 198)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [P.], cksum 0x77a3 (correct), seq 170:316, ack 3580, win 1179, options [nop,nop,TS val 109177 ecr 32995745], length 146
14:16:10.944570 IP (tos 0×0, ttl 64, id 47549, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [F.], cksum 0xeb94 (correct), seq 316, ack 3580, win 1179, options [nop,nop,TS val 109179 ecr 32995745], length 0
14:16:10.980757 IP (tos 0×0, ttl 64, id 61973, offset 0, flags [DF], proto TCP (6), length 60)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [S], cksum 0×1779 (correct), seq 2297190507, win 29200, options [mss 1460,sackOK,TS val 109182 ecr 0,nop,wscale 5], length 0
14:16:11.006680 IP (tos 0×58, ttl 108, id 10004, offset 0, flags [DF], proto TCP (6), length 111)
104.40.49.44.8883 > 10.53.230.46.34357: Flags [P.], cksum 0x11ce (correct), seq 3580:3639, ack 316, win 512, options [nop,nop,TS val 32995767 ecr 109177], length 59
14:16:11.007061 IP (tos 0×58, ttl 64, id 124, offset 0, flags [DF], proto TCP (6), length 40)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [R], cksum 0xc861 (correct), seq 2686457022, win 0, length 0
14:16:11.022686 IP (tos 0×58, ttl 108, id 10005, offset 0, flags [DF], proto TCP (6), length 52)
104.40.49.44.8883 > 10.53.230.46.34357: Flags [.], cksum 0xeddc (correct), ack 317, win 512, options [nop,nop,TS val 32995769 ecr 109179], length 0
14:16:11.023082 IP (tos 0×58, ttl 64, id 125, offset 0, flags [DF], proto TCP (6), length 40)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [R], cksum 0xc860 (correct), seq 2686457023, win 0, length 0
14:16:11.023201 IP (tos 0×58, ttl 108, id 10006, offset 0, flags [DF], proto TCP (6), length 52)
104.40.49.44.8883 > 10.53.230.46.34357: Flags [F.], cksum 0xeddb (correct), seq 3639, ack 317, win 512, options [nop,nop,TS val 32995769 ecr 109179], length 0
14:16:11.023618 IP (tos 0×58, ttl 64, id 126, offset 0, flags [DF], proto TCP (6), length 40)
10.53.230.46.34357 > 104.40.49.44.8883: Flags [R], cksum 0xc860 (correct), seq 2686457023, win 0, length 0
14:16:11.047669 IP (tos 0×58, ttl 108, id 27435, offset 0, flags [DF], proto TCP (6), length 60)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [S.], cksum 0x015a (correct), seq 2305905614, ack 2297190508, win 8192, options [mss 1380,nop,wscale 8,sackOK,TS val 33130802 ecr 109182], length 0
14:16:11.048047 IP (tos 0×0, ttl 64, id 61974, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [.], cksum 0x4c3f (correct), ack 1, win 913, options [nop,nop,TS val 109189 ecr 33130802], length 0
14:16:11.049574 IP (tos 0×0, ttl 64, id 61975, offset 0, flags [DF], proto TCP (6), length 221)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [P.], cksum 0xf567 (correct), seq 1:170, ack 1, win 913, options [nop,nop,TS val 109189 ecr 33130802], length 169
14:16:11.130033 IP (tos 0×58, ttl 108, id 27436, offset 0, flags [DF], proto TCP (6), length 1420)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [.], cksum 0x4d62 (correct), seq 1:1369, ack 170, win 513, options [nop,nop,TS val 33130810 ecr 109189], length 1368
14:16:11.130377 IP (tos 0×0, ttl 64, id 61976, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [.], cksum 0x45d4 (correct), ack 1369, win 1003, options [nop,nop,TS val 109197 ecr 33130810], length 0
14:16:11.134403 IP (tos 0×58, ttl 108, id 27437, offset 0, flags [DF], proto TCP (6), length 1420)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [.], cksum 0x7fa4 (correct), seq 1369:2737, ack 170, win 513, options [nop,nop,TS val 33130810 ecr 109189], length 1368
14:16:11.134811 IP (tos 0×0, ttl 64, id 61977, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [.], cksum 0×4020 (correct), ack 2737, win 1094, options [nop,nop,TS val 109198 ecr 33130810], length 0
14:16:11.134941 IP (tos 0×58, ttl 108, id 27438, offset 0, flags [DF], proto TCP (6), length 895)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [P.], cksum 0x6ffa (correct), seq 2737:3580, ack 170, win 513, options [nop,nop,TS val 33130810 ecr 109189], length 843
14:16:11.135209 IP (tos 0×0, ttl 64, id 61978, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [.], cksum 0x3c80 (correct), ack 3580, win 1179, options [nop,nop,TS val 109198 ecr 33130810], length 0
14:16:11.310418 IP (tos 0×0, ttl 64, id 61979, offset 0, flags [DF], proto TCP (6), length 198)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [P.], cksum 0×7374 (correct), seq 170:316, ack 3580, win 1179, options [nop,nop,TS val 109215 ecr 33130810], length 146
14:16:11.397674 IP (tos 0×58, ttl 108, id 27439, offset 0, flags [DF], proto TCP (6), length 111)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [P.], cksum 0xdba0 (correct), seq 3580:3639, ack 316, win 512, options [nop,nop,TS val 33130837 ecr 109215], length 59
14:16:11.397996 IP (tos 0×0, ttl 64, id 61980, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [.], cksum 0x3b7e (correct), ack 3639, win 1179, options [nop,nop,TS val 109224 ecr 33130837], length 0
14:16:11.410963 IP (tos 0×0, ttl 64, id 61981, offset 0, flags [DF], proto TCP (6), length 430)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [P.], cksum 0x45f0 (correct), seq 316:694, ack 3639, win 1179, options [nop,nop,TS val 109225 ecr 33130837], length 378
14:16:11.508708 IP (tos 0×58, ttl 108, id 27440, offset 0, flags [DF], proto TCP (6), length 89)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [P.], cksum 0x352f (correct), seq 3639:3676, ack 694, win 510, options [nop,nop,TS val 33130848 ecr 109225], length 37
14:16:11.519449 IP (tos 0×0, ttl 64, id 61982, offset 0, flags [DF], proto TCP (6), length 254)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [P.], cksum 0xd4c3 (correct), seq 694:896, ack 3676, win 1179, options [nop,nop,TS val 109236 ecr 33130848], length 202
14:16:11.594712 IP (tos 0×58, ttl 108, id 27441, offset 0, flags [DF], proto TCP (6), length 89)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [P.], cksum 0x62a9 (correct), seq 3676:3713, ack 896, win 510, options [nop,nop,TS val 33130857 ecr 109236], length 37
14:16:11.595026 IP (tos 0×0, ttl 64, id 61983, offset 0, flags [DF], proto TCP (6), length 712)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [P.], cksum 0xc513 (correct), seq 896:1556, ack 3713, win 1179, options [nop,nop,TS val 109244 ecr 33130857], length 660
14:16:11.687666 IP (tos 0×58, ttl 108, id 27442, offset 0, flags [DF], proto TCP (6), length 89)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [P.], cksum 0xd2be (correct), seq 3713:3750, ack 1556, win 513, options [nop,nop,TS val 33130866 ecr 109244], length 37
14:16:11.687985 IP (tos 0×0, ttl 64, id 61984, offset 0, flags [DF], proto TCP (6), length 158)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [P.], cksum 0xbeda (correct), seq 1556:1662, ack 3750, win 1179, options [nop,nop,TS val 109253 ecr 33130866], length 106
14:16:11.767753 IP (tos 0×58, ttl 108, id 27443, offset 0, flags [DF], proto TCP (6), length 233)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [P.], cksum 0x915a (correct), seq 3750:3931, ack 1662, win 512, options [nop,nop,TS val 33130874 ecr 109253], length 181
14:16:11.790701 IP (tos 0×58, ttl 108, id 27444, offset 0, flags [DF], proto TCP (6), length 137)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [P.], cksum 0x1d82 (correct), seq 3931:4016, ack 1662, win 512, options [nop,nop,TS val 33130877 ecr 109253], length 85
14:16:11.791271 IP (tos 0×0, ttl 64, id 61985, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [.], cksum 0×3421 (correct), ack 4016, win 1265, options [nop,nop,TS val 109263 ecr 33130874], length 0
14:16:12.052501 IP (tos 0×0, ttl 64, id 61986, offset 0, flags [DF], proto TCP (6), length 126)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [P.], cksum 0×0459 (correct), seq 1662:1736, ack 4016, win 1265, options [nop,nop,TS val 109289 ecr 33130874], length 74
14:16:12.052830 IP (tos 0×0, ttl 64, id 61987, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [F.], cksum 0x33bc (correct), seq 1736, ack 4016, win 1265, options [nop,nop,TS val 109289 ecr 33130874], length 0
14:16:12.316726 IP (tos 0×58, ttl 108, id 27445, offset 0, flags [DF], proto TCP (6), length 52)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [.], cksum 0×3676 (correct), ack 1737, win 512, options [nop,nop,TS val 33130929 ecr 109289], length 0
14:16:12.318208 IP (tos 0×58, ttl 108, id 27446, offset 0, flags [DF], proto TCP (6), length 52)
104.40.49.44.8883 > 10.53.230.46.34358: Flags [F.], cksum 0×3675 (correct), seq 4016, ack 1737, win 512, options [nop,nop,TS val 33130929 ecr 109289], length 0
14:16:12.318641 IP (tos 0×0, ttl 64, id 170, offset 0, flags [DF], proto TCP (6), length 52)
10.53.230.46.34358 > 104.40.49.44.8883: Flags [.], cksum 0×3369 (correct), ack 4017, win 1265, options [nop,nop,TS val 109316 ecr 33130929], length 0
^C
52 packets captured
52 packets received by filter
0 packets dropped by kernel