diff --git a/include/patty/ax25/sock.h b/include/patty/ax25/sock.h
index 6ee6c75..71ff5f0 100644
--- a/include/patty/ax25/sock.h
+++ b/include/patty/ax25/sock.h
@@ -17,7 +17,7 @@
    | PATTY_AX25_PARAM_HDLC_XADDR | PATTY_AX25_PARAM_HDLC_MODULO_8 \
    | PATTY_AX25_PARAM_HDLC_TEST  | PATTY_AX25_PARAM_HDLC_SYNC_TX)
 
-#define PATTY_AX25_SOCK_DEFAULT_I_LEN   256
+#define PATTY_AX25_SOCK_DEFAULT_I_LEN   128
 #define PATTY_AX25_SOCK_DEFAULT_WINDOW    4
 #define PATTY_AX25_SOCK_DEFAULT_RETRY    10
 #define PATTY_AX25_SOCK_DEFAULT_ACK    3000
@@ -31,7 +31,7 @@
    | PATTY_AX25_PARAM_HDLC_TEST        | PATTY_AX25_PARAM_HDLC_FCS_16 \
    | PATTY_AX25_PARAM_HDLC_SYNC_TX)
 
-#define PATTY_AX25_SOCK_2_2_DEFAULT_I_LEN  256
+#define PATTY_AX25_SOCK_2_2_DEFAULT_I_LEN  255
 #define PATTY_AX25_SOCK_2_2_DEFAULT_WINDOW  32
 
 /*