ASN AS19977 is an Autonomous System Number used to identify a network for BGP internet routing.

Who manages ASN AS19977?

AS19977 is listed under Mayer Brown LLP.

What do peers, upstreams, and downstreams mean in ASN data?

Peers are lateral network interconnections, upstreams are transit providers, and downstreams are customer networks receiving connectivity.

What are routes and IP ranges for an ASN?

Routes and IP ranges are the network prefixes announced by the ASN on the internet and show the address space it originates.

Why is WHOIS data shown for an ASN?

WHOIS data provides registration and contact context for ASN ownership, administration, and operational reference.

How can I access the full ASN tables?

The page shows a preview of large ASN datasets. Use the page controls to load more rows, and upgrade to a paid plan for complete access.

AS19977 Mayer Brown LLP | IPGeolocation.io

ASN Lookup Tool

Mayer Brown LLP mayerbrown.com

US 10 Routes

AS Data

AS19977

AS19977 – Mayer Brown LLP

AS Number	19977
AS Name	MBRML-AS
Organization	Mayer Brown LLP(mbrml)
Country	US
Website	mayerbrown.com
Number of IPv4 Routes	10
Number of IPv6 Routes	0
ASN type	BUSINESS
Registry	ARIN
Date Allocated	2016-08-02

ASN Intelligence API for production workflows

Use ASN data for AS19977 in automation: routing intelligence, peering analysis, ownership checks, and network observability.

Access complete peers, upstreams, downstreams, routes, WHOIS, and contact intelligence via our API. Learn more

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IP Ranges

Route	Origin	Origin Name	ISP	# IPs
143.58.0.0/22	AS19977	Mayer Brown LLP	Mayer Brown LLP	1024
143.58.7.0/24	AS19977	Mayer Brown LLP	Mayer Brown LLP	256
143.58.6.0/24	AS19977	Mayer Brown LLP	Mayer Brown LLP	256
143.58.5.0/24	AS19977	Mayer Brown LLP	Mayer Brown LLP	256
143.58.0.0/24	AS19977	Mayer Brown LLP	Mayer Brown LLP	256
143.58.3.0/24	AS19977	Mayer Brown LLP	Mayer Brown LLP	256
143.58.2.0/24	AS19977	Mayer Brown LLP	Mayer Brown LLP	256
143.58.1.0/24	AS19977	Mayer Brown LLP	Mayer Brown LLP	256
143.58.4.0/22	AS19977	Mayer Brown LLP	Mayer Brown LLP	1024
143.58.4.0/24	AS19977	Mayer Brown LLP	Mayer Brown LLP	256

Raw Whois Response

#
# ARIN WHOIS data and services are subject to the Terms of Use
# available at: https://www.arin.net/resources/registry/whois/tou/
#
# If you see inaccuracies in the results, please report at
# https://www.arin.net/resources/registry/whois/inaccuracy_reporting/
#
# Copyright 1997-2026, American Registry for Internet Numbers, Ltd.
#


ASNumber:       19977
ASName:         MBRML-AS
ASHandle:       AS19977
RegDate:        2016-08-02
Updated:        2016-08-02    
Ref:            https://rdap.arin.net/registry/autnum/19977


OrgName:        Mayer Brown LLP
OrgId:          MBRML
Address:        71 S. Wacker
City:           Chicago
StateProv:      IL
PostalCode:     60606
Country:        US
RegDate:        2006-01-12
Updated:        2016-07-12
Ref:            https://rdap.arin.net/registry/entity/MBRML


OrgTechHandle: MCS7-ARIN
OrgTechName:   Sherman, Michael C
OrgTechPhone:  +1-312-701-8315 
OrgTechEmail:  msherman@mayerbrown.com
OrgTechRef:    https://rdap.arin.net/registry/entity/MCS7-ARIN

OrgAbuseHandle: MCS7-ARIN
OrgAbuseName:   Sherman, Michael C
OrgAbusePhone:  +1-312-701-8315 
OrgAbuseEmail:  msherman@mayerbrown.com
OrgAbuseRef:    https://rdap.arin.net/registry/entity/MCS7-ARIN


#
# ARIN WHOIS data and services are subject to the Terms of Use
# available at: https://www.arin.net/resources/registry/whois/tou/
#
# If you see inaccuracies in the results, please report at
# https://www.arin.net/resources/registry/whois/inaccuracy_reporting/
#
# Copyright 1997-2026, American Registry for Internet Numbers, Ltd.
#

Parsed Whois Response

Peers

AS Number	Description	Country
AS1239	Cogent Communications, LLC	US
AS3356	Level 3 Parent, LLC	US
AS174	Cogent Communications, LLC	US

Upstreams

AS Number	Description	Country
AS3356	Level 3 Parent, LLC	US
AS174	Cogent Communications, LLC	US