diff --git a/src/DPD/pair_dpd.cpp b/src/DPD/pair_dpd.cpp
index c1602a69b1..7bea9574cc 100644
--- a/src/DPD/pair_dpd.cpp
+++ b/src/DPD/pair_dpd.cpp
@@ -202,8 +202,7 @@ void PairDPD::settings(int narg, char **arg)
 
   // initialize Marsaglia RNG with processor-unique seed
 
-  if (seed <= 0 || seed > 900000000)
-    error->all("Illegal fix pair_style command");
+  if (seed <= 0) error->all("Illegal fix pair_style command");
   if (random) delete random;
   random = new RanMars(lmp,seed + comm->me);
 
diff --git a/src/GRANULAR/fix_pour.cpp b/src/GRANULAR/fix_pour.cpp
index a392c5b6a8..c580123c53 100644
--- a/src/GRANULAR/fix_pour.cpp
+++ b/src/GRANULAR/fix_pour.cpp
@@ -51,6 +51,8 @@ FixPour::FixPour(LAMMPS *lmp, int narg, char **arg) :
   ntype = atoi(arg[4]);
   seed = atoi(arg[5]);
 
+  if (seed <= 0) error->all("Illegal fix pour command");
+
   PI = 4.0*atan(1.0);
 
   // option defaults
diff --git a/src/displace_atoms.cpp b/src/displace_atoms.cpp
index 6bb5ffab99..ab32959e80 100644
--- a/src/displace_atoms.cpp
+++ b/src/displace_atoms.cpp
@@ -175,6 +175,7 @@ void DisplaceAtoms::command(int narg, char **arg)
     double dy = yscale*atof(arg[3]);
     double dz = zscale*atof(arg[4]);
     int seed = atoi(arg[5]);
+    if (seed <= 0) error->all("Illegal displace_atoms random command");
 
     double **x = atom->x;
     int *mask = atom->mask;
diff --git a/src/fix_deposit.cpp b/src/fix_deposit.cpp
index 24d1ec2388..fbaa5f4b81 100644
--- a/src/fix_deposit.cpp
+++ b/src/fix_deposit.cpp
@@ -43,6 +43,8 @@ FixDeposit::FixDeposit(LAMMPS *lmp, int narg, char **arg) :
   nfreq = atoi(arg[5]);
   seed = atoi(arg[6]);
 
+  if (seed <= 0) error->all("Illegal fix deposit command");
+
   // set defaults
 
   iregion = -1;
diff --git a/src/fix_indent.h b/src/fix_indent.h
index f64b5bf62e..f0604146da 100644
--- a/src/fix_indent.h
+++ b/src/fix_indent.h
@@ -25,13 +25,13 @@ class FixIndent : public Fix {
   void init();
   void setup();
   void min_setup();
-  void post_force(int);
+  virtual void post_force(int);
   void post_force_respa(int, int, int);
   void min_post_force(int);
   double compute_scalar();
   double compute_vector(int);
 
- private:
+ protected:
   int istyle,scaleflag,radflag,thermo_flag,eflag_enable;
   double k,k3;
   double x0,y0,z0,r0_stop,r0_start;
diff --git a/src/fix_langevin.cpp b/src/fix_langevin.cpp
index 4753845af7..7fb556639e 100644
--- a/src/fix_langevin.cpp
+++ b/src/fix_langevin.cpp
@@ -41,8 +41,7 @@ FixLangevin::FixLangevin(LAMMPS *lmp, int narg, char **arg) :
   int seed = atoi(arg[6]);
 
   if (t_period <= 0.0) error->all("Fix langevin period must be > 0.0");
-  if (seed <= 0 || seed > 900000000)
-    error->all("Illegal fix langevin command");
+  if (seed <= 0) error->all("Illegal fix langevin command");
 
   // initialize Marsaglia RNG with processor-unique seed
 
diff --git a/src/random_park.cpp b/src/random_park.cpp
index 47c408e7fa..0c01d1eb8c 100644
--- a/src/random_park.cpp
+++ b/src/random_park.cpp
@@ -40,7 +40,7 @@ using namespace LAMMPS_NS;
 
 RanPark::RanPark(LAMMPS *lmp, int seed_init) : Pointers(lmp)
 {
-  if (seed_init == 0) error->all("Invalid seed for Park random # generator");
+  if (seed_init <= 0) error->all("Invalid seed for Park random # generator");
   seed = seed_init;
   save = 0;
 }
diff --git a/src/velocity.cpp b/src/velocity.cpp
index 138891fc30..8747dcebae 100644
--- a/src/velocity.cpp
+++ b/src/velocity.cpp
@@ -126,6 +126,8 @@ void Velocity::create(int narg, char **arg)
   double t_desired = atof(arg[0]);
   int seed = atoi(arg[1]);
 
+  if (seed <= 0) error->all("Illegal velocity create command");
+
   // if temperature = NULL, create a new ComputeTemp with the velocity group
 
   int tflag = 0;