c7800 drops internet, wifi stays connected +DOS attacks

This has been a persistent problem since I got this modem/router. Have Xfinity service. Randomly throughout the day the internet will drop connection. The wifi signals continue to broadcast but my android phone will tell me connected to wifi no internet. A lot of times I will go to the router and look and all 4 lights will be lit like normal with the 2.4 and 5ghz wifi lights flashing like normal. Sometimes a couple lights will be out.

The internet will not restore until I power cycle the modem. I have to do this quite often. Xfinity blames netgear cause a tech has been out 3 times for this issues but it is always working fine when they come out, and they say the line is good to the house, or if I get someone on the phone while it is down the power cycle will restore it and they think they fixed it. 

A tech is coming out to replace the line from the pole to my house tomorrow, but I've already ordered ATT at a significantly slower speed for only $10 less a month. I would like to stay with the cable if possible. 

Also I am getting DOS attacked on the regular from checking my logs. But there is no way to blacklist IP's.  I thought I remembered something about built in DOS protection coming with this modem. 

Here is log.

[admin login] from source 192.168.0.8, Tue, May 19, 2020 08:23:37
[DoS attack: Sync flood] from source: 207.96.160.98, port 80, Tue, May 19, 2020 08:11:33
[DoS attack: Sync flood] from source: 104.37.191.10, port 443, Tue, May 19, 2020 07:24:46
[DoS attack: Sync flood] from source: 13.225.48.182, port 80, Tue, May 19, 2020 05:23:06
[DoS attack: Sync flood] from source: 60.169.79.121, port 6000, Tue, May 19, 2020 05:14:13
[DoS attack: UDP Scan] from source: 42.240.129.58, port 58914, Tue, May 19, 2020 04:57:59
[DoS attack: Sync flood] from source: 87.251.75.124, port 2048, Tue, May 19, 2020 03:31:48
[DoS attack: Sync flood] from source: 112.28.85.85, port 51046, Tue, May 19, 2020 01:22:54
[DoS attack: UDP Scan] from source: 185.94.111.1, port 34908, Mon, May 18, 2020 22:48:25
[DoS attack: Echo char gen] from source: 71.6.232.5, port 59601, Mon, May 18, 2020 21:49:44
[DoS attack: Sync flood] from source: 104.37.191.10, port 443, Mon, May 18, 2020 21:45:05
[DoS attack: Sync flood] from source: 104.37.191.10, port 443, Mon, May 18, 2020 21:44:25
[DoS attack: Sync flood] from source: 104.37.191.10, port 443, Mon, May 18, 2020 21:43:45
[admin login] from source 192.168.0.8, Mon, May 18, 2020 20:55:47
[admin login failure] from source 192.168.0.8, Mon, May 18, 2020 20:55:42
[DoS attack: Sync flood] from source: 23.246.2.174, port 443, Mon, May 18, 2020 20:16:29
[DoS attack: UDP Scan] from source: 185.94.111.1, port 60057, Mon, May 18, 2020 19:49:55
[DoS attack: Echo char gen] from source: 146.88.240.4, port 58010, Mon, May 18, 2020 19:38:54
[DoS attack: UDP Scan] from source: 42.240.129.58, port 58914, Mon, May 18, 2020 18:29:02
[Internet connected] IP address: 71.XXX.XXX.57, Mon, May 18, 2020 17:17:04
[Internet disconnected] Mon, May 18, 2020 17:16:32
[Internet connected] IP address: 71.XXX.XXX.57, Mon, May 18, 2020 17:02:57
[Internet disconnected] Mon, May 18, 2020 16:54:29
[DoS attack: UDP Scan] from source: 106.75.141.155, port 58914, Mon, May 18, 2020 15:02:38
[DoS attack: Sync flood] from source: 45.227.255.59, port 65533, Mon, May 18, 2020 13:04:07
[DoS attack: Echo char gen] from source: 104.152.52.25, port 56541, Mon, May 18, 2020 11:04:09
[DoS attack: UDP Scan] from source: 104.152.52.25, port 56541, Mon, May 18, 2020 11:03:40
[DoS attack: UDP Scan] from source: 104.152.52.25, port 56541, Mon, May 18, 2020 10:52:40
[DoS attack: UDP Scan] from source: 104.152.52.25, port 56541, Mon, May 18, 2020 10:42:31
[DHCP IP: (192.168.0.2)] to MAC address 26:e1:29:b1:aa:de, Mon, May 18, 2020 10:04:36
[DoS attack: Sync flood] from source: 104.18.9.161, port 443, Mon, May 18, 2020 10:03:52
[DoS attack: Sync flood] from source: 205.185.216.42, port 80, Mon, May 18, 2020 09:52:40
[DoS attack: Sync flood] from source: 104.18.218.73, port 443, Mon, May 18, 2020 09:51:13
[DoS attack: UDP Scan] from source: 198.108.67.30, port 65351, Mon, May 18, 2020 08:46:41
[DoS attack: Ascend Kill attack] from source: 89.248.168.217, port 34290, Mon, May 18, 2020 07:53:27
[DoS attack: Sync flood] from source: 218.60.25.225, port 14101, Mon, May 18, 2020 06:59:26
[DoS attack: Echo char gen] from source: 184.105.139.97, port 3500, Mon, May 18, 2020 04:43:23
[DoS attack: Echo char gen] from source: 52.73.169.169, port 42540, Mon, May 18, 2020 02:57:13
[DoS attack: Sync flood] from source: 13.226.185.82, port 443, Sun, May 17, 2020 23:19:45
[DoS attack: UDP Scan] from source: 146.88.240.4, port 33208, Sun, May 17, 2020 22:54:19
[DoS attack: Sync flood] from source: 13.249.79.219, port 80, Sun, May 17, 2020 22:46:18
[DHCP IP: (192.168.0.13)] to MAC address 60:f8:1d:b8:bb:24, Sun, May 17, 2020 22:17:48
[DoS attack: UDP Scan] from source: 106.75.63.218, port 55216, Sun, May 17, 2020 21:00:23
[admin login] from source 192.168.0.8, Sun, May 17, 2020 20:25:28
[admin login failure] from source 192.168.0.8, Sun, May 17, 2020 20:25:25
[DoS attack: Sync flood] from source: 152.195.33.40, port 443, Sun, May 17, 2020 20:24:56
[DoS attack: Echo char gen] from source: 83.97.20.35, port 52762, Sun, May 17, 2020 20:20:28
[admin login] from source 192.168.0.8, Sun, May 17, 2020 20:19:39
[DHCP IP: (192.168.0.12)] to MAC address 82:11:07:99:ee:16, Sun, May 17, 2020 20:13:07
[DoS attack: Echo char gen] from source: 183.136.225.45, port 34545, Sun, May 17, 2020 20:09:40
[DoS attack: Sync flood] from source: 13.225.53.113, port 80, Sun, May 17, 2020 19:56:27
[DoS attack: Sync flood] from source: 13.225.53.113, port 80, Sun, May 17, 2020 19:49:49
[DoS attack: Echo char gen] from source: 146.88.240.4, port 53625, Sun, May 17, 2020 19:38:52
[DHCP IP: (192.168.0.9)] to MAC address f4:5c:89:bc:f5:4b, Sun, May 17, 2020 19:31:18
[DHCP IP: (192.168.0.11)] to MAC address 32:d8:1a:01:fd:ae, Sun, May 17, 2020 19:28:18
[DHCP IP: (192.168.0.7)] to MAC address 64:1c:ae:66:35:0e, Sun, May 17, 2020 19:27:12
[DHCP IP: (192.168.0.8)] to MAC address c4:9d:ed:2a:70:b2, Sun, May 17, 2020 19:27:04
[Time synchronized with NTP server] Sun, May 17, 2020 19:26:57
[Internet connected] IP address: 71.XXX.XXX.57, Wed, Dec 31, 1969 18:01:08
[DHCP IP: (192.168.0.10)] to MAC address 4c:b1:99:04:c6:9c, Wed, Dec 31, 1969 18:01:06
[DHCP IP: (192.168.0.6)] to MAC address f8:36:9b:3b:84:1c, Wed, Dec 31, 1969 18:01:05
[DHCP IP: (192.168.0.5)] to MAC address 80:e8:2c:89:f7:e3, Wed, Dec 31, 1969 18:01:01
[DHCP IP: (192.168.0.3)] to MAC address 3c:e1:a1:ac:e3:19, Wed, Dec 31, 1969 18:00:58
[Initialized, firmware version: V3.01.43] Thu, Jan 01, 1970 00:00:07
[DoS attack: Echo char gen] from source: 45.33.98.221, port 52953, Mon, May 18, 2020 00:17:35
[DHCP IP: (192.168.0.11)] to MAC address 32:d8:1a:01:fd:ae, Mon, May 18, 2020 00:16:50
[admin login] from source 192.168.0.8, Mon, May 18, 2020 00:16:25
[admin login failure] from source 192.168.0.8, Mon, May 18, 2020 00:16:19
[DHCP IP: (192.168.0.7)] to MAC address 64:1c:ae:66:35:0e, Mon, May 18, 2020 00:15:13
[DHCP IP: (192.168.0.6)] to MAC address f8:36:9b:3b:84:1c, Mon, May 18, 2020 00:15:07
[Time synchronized with NTP server] Mon, May 18, 2020 00:15:03
[DHCP IP: (192.168.0.8)] to MAC address c4:9d:ed:2a:70:b2, Thu, Jan 01, 1970 00:01:18
[Internet connected] IP address: 71.XXX.XXX.57, Thu, Jan 01, 1970 00:01:14
[DHCP IP: (192.168.0.10)] to MAC address 4c:b1:99:04:c6:9c, Thu, Jan 01, 1970 00:01:08
[DHCP IP: (192.168.0.5)] to MAC address 80:e8:2c:89:f7:e3, Thu, Jan 01, 1970 00:01:03
[DHCP IP: (192.168.0.9)] to MAC address f4:5c:89:bc:f5:4b, Thu, Jan 01, 1970 00:01:03
[DHCP IP: (192.168.0.3)] to MAC address 3c:e1:a1:ac:e3:19, Thu, Jan 01, 1970 00:00:59
[Initialized, firmware version: V3.01.43] Thu, Jan 01, 1970 00:00:07
[DHCP IP: (192.168.0.8)] to MAC address c4:9d:ed:2a:70:b2, Mon, May 18, 2020 00:11:50
[Time synchronized with NTP server] Mon, May 18, 2020 00:11:35
[Internet connected] IP address: 71.XXX.XXX.51, Thu, Jan 01, 1970 00:02:30
[DHCP IP: (192.168.0.7)] to MAC address 64:1c:ae:66:35:0e, Thu, Jan 01, 1970 00:02:12
[DHCP IP: (192.168.0.6)] to MAC address f8:36:9b:3b:84:1c, Thu, Jan 01, 1970 00:01:21
[DHCP IP: (192.168.0.4)] to MAC address 80:e8:2c:89:f7:e3, Thu, Jan 01, 1970 00:01:06
[DHCP IP: (192.168.0.3)] to MAC address 3c:e1:a1:ac:e3:19, Thu, Jan 01, 1970 00:01:02
[DHCP IP: (192.168.0.2)] to MAC address 26:e1:29:b1:aa:de, Thu, Jan 01, 1970 00:00:56
[Initialized, firmware version: V3.01.43] Thu, Jan 01, 1970 00:00:07