Robtex

Up: 206.227.128.0/17
Can't show all results, try to descend to a more specific CIDR
Down left: 206.227.128.0/19
Down right: 206.227.160.0/19
(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
206.227.129.70	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
206.227.137.50	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
206.227.137.81	A	e-contract.txuenergy.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
206.227.137.193	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
206.227.137.246	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	A	webmail.energyfutureholdings.com
206.227.143.50	A	webmail.vistraenergy.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
206.227.160.10	A	moe.txu.com
206.227.160.81	A+PTR	ddcspmrb01.txu.com
206.227.161.20	PTR	oncorwebapps.oncor.com
206.227.161.20	PTR	oncorwebapps.oncorgroup.com
206.227.161.20	PTR	txuwebapps.txu.com
206.227.161.27	PTR	esbdmz03.oncorgroup.com
206.227.161.28	PTR	www5.tu.com
206.227.161.28	PTR	www5.txu.com
206.227.161.29	PTR	streetlights.oncor.com
206.227.161.245	A+PTR	esbxd09b.txu.com
206.227.169.63	A	drwebmail.energyfutureholdings.com
206.227.169.90	A	dmxsmtp01.oncor.com
206.227.169.91	A	dmxsmtp01ob.txu.com
206.227.169.91	A	dmxsmtp01ob.oncor.com
206.227.169.121	A	e-contract.txuenergy.com
206.227.169.177	A	nodaltst2.luminant.com
206.227.169.178	A	nodaldev.luminant.com
206.227.169.200	A+PTR	webmaila.txu.com
206.227.169.219	A+PTR	nodaltst3.luminant.com
206.227.169.245	A+PTR	ddcxc01c.txu.com
206.227.170.38	PTR	txuehistory.com
206.227.170.38	PTR	txuesgateway.com
206.227.170.38	PTR	www.txuehistory.com