diff --git a/src/system/imp.367 b/src/system/imp.368
similarity index 97%
rename from src/system/imp.367
rename to src/system/imp.368
index 47927dc1..16a400e8 100644
--- a/src/system/imp.367
+++ b/src/system/imp.368
@@ -607,8 +607,29 @@ IMPGD:	LDB B,[420200,,IMPILB+2]	;Reason (see 1822)
 	JRST IMPIRT
 
 ;;; IMP->Host Type 4 - NOP
+;;; With support in KLH10 (dpimp version 1.1.4 or later),
+;;; read the IP configuration from the NOP sent.
+;;; The IP address is in the network, source host, and source IMP fields,
+;;; and the subnet mask size is in the "handling type" field.
+;;; The first and last of these are very non-standard, but hey... it works.
 
-IMPIN:	JRST IMPIRT		;One more NOP from IMP
+IMPIN:	LDB T,[241000,,IMPILB+0]	;get network byte (ip[0])
+	JUMPE T,IMPIRT		; none: incompatible IMP code
+	LSH T,24.
+	LDB TT,IMSABP		; get source host+IMP (ip[1..3])
+	IOR T,TT
+	MOVEM T,NIFIPA		; save our IP address
+	LDB T,[341000,,IMPILB+1]	; get subnet mask size
+	SUBI T,32.		; bits to shift
+	HRLOI TT,37777		; 32 bits set
+	LSH TT,(T)		; shift right
+	MOVNS T	
+	LSH TT,(T)		; shift left again
+	MOVEM TT,NIFIPM
+	MOVE T,NIFIPA		; make network part of address
+	AND T,NIFIPM
+	MOVEM T,NIFIPN		; save it
+	JRST IMPIRT		;One more NOP from IMP
 
 ;;; IMP->Host Type 5 - RFNM (Ready For Next Message)