--- src/comsat.c.old	2005-08-17 19:17:20.000000000 +0200
+++ src/comsat.c	2005-08-17 19:18:19.000000000 +0200
@@ -92,7 +92,7 @@
    }
   if(newvalid)						  /* so far, so good */
    { int s;
-     if(!*chp)						       /* no service */
+     if(!chad||!*chp)						       /* no service */
 	chp=BIFF_serviceport;				/* new balls please! */
      s=strtol(chp,&chad,10);
      if(chp!=chad)			       /* the service is not numeric */
@@ -120,7 +120,7 @@
 { int s;const char*p;
   if(!csvalid||!buf)		  /* is comat on and set to a valid address? */
      return;
-  if(!*cslgname||strlen(cslgname)+2>linebuf)	       /* is $LOGNAME bogus? */
+  if(!cslgname||!*cslgname||strlen(cslgname)+2>linebuf)	       /* is $LOGNAME bogus? */
      return;
   if(!(p=folder?folder:cslastf))		     /* do we have a folder? */
      return;