IP Address: 148.163.133.153 ⚠ Network Confounder

⚠ Network Confounder Detected: Proofpoint Email Security
Proofpoint network identifier

This page shows DMARC authentication failure data for this IP address. Learn more about this data.

Geolocation Information

Country:: US United States
Region:: California
Coordinates:: 34.0544, -118.244

WHOIS Information

Network Name:: PROOFPOINT-NET-NORTH-AMERICA
CIDR:: 148.163.128.0/19
Owner:: Proofpoint, Inc.
Org ID:: PROOF
Address:: 925 W Maude Ave, Sunnyvale, CA 94085
Reverse DNS:: mx0a-00174802.pphosted.com
Last updated: 2/5/2026

Analysis

This IP was first observed on April 16, 2025 and most recently on April 7, 2026. It has been associated with 18 failed authentication events affecting 20 messages, representing moderate activity. The IP belongs to PROOFPOINT-NET-NORTH-AMERICA (Proofpoint, Inc.), a network with activity associated with United States. One other IP in the same /24 subnet (148.163.133.*) also appears in this dataset.

Failures Detected from this IP

Showing 1-18 of 18 failures, affecting 20 messages

Date ▼	Messages
4/7/2026	1
3/24/2026	1
1/28/2026	1
1/7/2026	1
12/16/2025	1
11/11/2025	1
10/21/2025	1
10/8/2025	1
10/1/2025	1
9/30/2025	1
9/10/2025	1
7/31/2025	1
7/18/2025	1
7/10/2025	1
7/9/2025	2
7/1/2025	2
5/1/2025	1
4/16/2025	1

External Reputation Lookups

Look up this IP in external threat intelligence and reputation databases (opens in new tab):

AbuseIPDB Cisco Talos Project Honey Pot GreyNoise VirusTotal Shodan Censys Spamhaus

Nearby IPs

Other IPs in the 148.163.133.0/24 range observed failing DMARC:

148.163.133.148 (2 failures)