diff --git a/README.md b/README.md
index 28b81ef..043a9b7 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,14 @@ sudo tcpdump -n -l dst net 192.0.2.1/32 $(for a in $(cat goog-prefixes.txt); do
 
 And then cry.
 
+## Problems
+If tcpdump complains about `Warning: Kernel filter failed: Cannot allocate memory`, try
+this first:
+
+```
+sudo sysctl net.core.optmem_max=204800
+```
+
 ## Data source
 The list of Google services IP addresses can be found on [this Google
 support page](https://support.google.com/a/answer/10026322?hl=en).
diff --git a/teller.cc b/teller.cc
index aa580c7..7dc4439 100644
--- a/teller.cc
+++ b/teller.cc
@@ -36,6 +36,8 @@ int main()
           data.push_back(val);
         }
         ourcounter++;
+        if(counter - ourcounter > 1000)
+          ourcounter = counter;
       }
       else {
         for(int n=0; n < 150; ++n) {