Robtex

Up: 206.227.128.0/18
Can't show all results, try to descend to a more specific CIDR
Down left: 206.227.128.0/20
Down right: 206.227.144.0/20
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
206.227.128.10	A+PTR	curly.txu.com
206.227.129.22	A	www9.txu.com
206.227.129.27	A+PTR	txuesweb.txu.com
206.227.129.30	A	dns01.txu.com
206.227.129.33	A	etesc.txu.com
206.227.129.39	A	txuetweb.txu.com
206.227.129.40	A+PTR	energy.txu.com
206.227.129.41	A	www3.txu.com
206.227.129.70	A+PTR	txuservices.com
206.227.129.70	A+PTR	www12.txu.com
206.227.129.70	A+PTR	www.txuservices.com
206.227.129.90	A	eptxudsx401.txu.com
206.227.129.100	PTR	mailhost10.oncorgroup.com
206.227.129.140	A	passthru1.txu.com
206.227.129.141	A	etx12.txu.com
206.227.129.153	A+PTR	webmail.txu.com
206.227.129.156	A	txuenergyaffiliate.com
206.227.129.240	A+PTR	epxxgss01.energyfutureholdings.com
206.227.129.240	A+PTR	epxxgss01.txu.com
206.227.129.245	A	epxxd25b.txu.com
206.227.129.246	A	sync0n.txu.com
206.227.136.23	A	mivsp.energyfutureholdings.com
206.227.136.80	A	mdcspmrb01.txu.com
206.227.137.21	PTR	txu-totalcomp.com
206.227.137.21	PTR	txuelectric.com
206.227.137.21	PTR	txuflexdimension.com
206.227.137.36	A	webtest.txu.com
206.227.137.37	A	marmaduke.txu.com
206.227.137.39	A	nsdns01.oncor.com
206.227.137.44	A	ftp.oncor.com
206.227.137.50	A	mmxsmtp01.oncor.com
206.227.137.51	A	ppmft.txu.com
206.227.137.70	PTR	streetlights.txuelectricdelivery.com
206.227.137.70	A	streetlights.oncor.com
206.227.137.70	A	streetlights.oncorgroup.com
206.227.137.71	A+PTR	maximotest.oncorgroup.com
206.227.137.71	PTR	maximotest.txuelectricdelivery.com
206.227.137.72	PTR	maximo.oncor.com
206.227.137.72	PTR	maximo.txuelectricdelivery.com
206.227.137.72	A	maximo.oncorgroup.com
206.227.137.126	A	tango.energyfutureholdings.com
206.227.137.127	A	mdctxuwiis15.txu.com
206.227.137.150	A	mmxsmtp01.oncor.com
206.227.137.151	A	mmxsmtp01ob.oncor.com
206.227.137.151	A	mmxsmtp01ob.txu.com
206.227.137.152	A	eas.txucorp.com
206.227.137.170	A	mdctxuteemiis.oncorgroup.com
206.227.137.175	A+PTR	txucorp.com
206.227.137.177	A+PTR	txugas.com
206.227.137.179	PTR	oncor.com
206.227.137.193	PTR	ac.txuelectricdelivery.com
206.227.137.193	A	accomm.oncor.com
206.227.137.199	A	acdist.oncor.com
206.227.137.219	A	autodiscover.luminant.com
206.227.137.219	A	legacy.energyfutureholdings.com
206.227.137.240	A+PTR	mdcxgss01.energyfutureholdings.com
206.227.137.240	A+PTR	mdcxgss01.txu.com
206.227.137.245	A+PTR	mdcxc01c.txu.com
206.227.137.246	A	sync0n.txu.com
206.227.138.38	PTR	txuehistory.com
206.227.138.38	PTR	txuesgateway.com
206.227.138.145	A	ppmft.txu.com
206.227.143.24	A	drwebmail.energyfutureholdings.com
206.227.143.35	A+PTR	nsglb1.txu.com
206.227.143.50	PTR	autodiscover.energyfutureholdings.com
206.227.143.50	A+PTR	webmail.energyfutureholdings.com
206.227.143.50	PTR	autodiscover.luminant.com
206.227.143.52	A+PTR	lists.luminant.com
206.227.143.52	PTR	lists.txu.com
206.227.143.52	PTR	lumlists.txu.com
206.227.143.124	PTR	businessinsights.txu.com
206.227.143.124	PTR	secure.txu.com
206.227.143.124	A+PTR	services.txu.com
206.227.143.125	PTR	secure.txu.com
206.227.144.51	A	webmail.energyfutureholdings.com
206.227.144.51	A	autodiscover.vistraenergy.com
206.227.149.10	A+PTR	kuan.txu.com
206.227.149.11	A	ftpmt.txu.com
206.227.149.12	A	gisbmt1.txu.com
206.227.149.12	A	gisbst1.txu.com