I noticed that a network connection through a wifi router is unstable. It started after some recent updates had been installed. For some time connection is lost then it appears again. The router itself is reachable and remote DNS server as well. But I can't load any webpage. Sometimes it's possible to connect though ftp protocol but not http. If I reconnect network is working for some time again.
Here's a system log from the period of time when the connection is lost:
Feb 29 16:10:26 alex kernel: [ 9213.060094] Scan in 40M, force to 20M first:3, 1
Feb 29 16:10:27 alex kernel: [ 9214.520074] Scan in 20M, back to 40M
Feb 29 16:10:27 alex kernel: [ 9214.530071] ===>rtl8192se_link_change():ieee->iw_mode is 2
Feb 29 16:10:27 alex kernel: [ 9214.530076] rtl8192_update_cap(): WLAN_CAPABILITY_SHORT_PREAMBLE
Feb 29 16:10:34 alex kernel: [ 9221.872059] SetHwReg8192SE():HW_VAR_AC_PARAM eACI:0:a42b
Feb 29 16:10:42 alex kernel: [ 9229.871812] SetHwReg8192SE():HW_VAR_AC_PARAM eACI:0:a42b
Feb 29 16:10:48 alex kernel: [ 9235.871383] SetHwReg8192SE():HW_VAR_AC_PARAM eACI:0:a42b
Feb 29 16:11:06 alex kernel: [ 9253.003305] ===>rtl8192se_link_change():ieee->iw_mode is 2
Feb 29 16:11:06 alex kernel: [ 9253.056590] Scan in 40M, force to 20M first:3, 1
Feb 29 16:11:07 alex kernel: [ 9254.516592] Scan in 20M, back to 40M
Feb 29 16:11:07 alex kernel: [ 9254.526600] ===>rtl8192se_link_change():ieee->iw_mode is 2
Feb 29 16:11:07 alex kernel: [ 9254.526606] rtl8192_update_cap(): WLAN_CAPABILITY_SHORT_PREAMBLE
Feb 29 16:11:10 alex kernel: [ 9257.871436] SetHwReg8192SE():HW_VAR_AC_PARAM eACI:0:a42b
Feb 29 16:11:14 alex kernel: [ 9261.871836] SetHwReg8192SE():HW_VAR_AC_PARAM eACI:0:a42b
Feb 29 16:11:30 alex kernel: [ 9277.871312] SetHwReg8192SE():HW_VAR_AC_PARAM eACI:0:a42b
Feb 29 16:11:46 alex kernel: [ 9293.871836] SetHwReg8192SE():HW_VAR_AC_PARAM eACI:0:a42b
Feb 29 16:12:06 alex kernel: [ 9313.002945] ===>rtl8192se_link_change():ieee->iw_mode is 2
Feb 29 16:12:06 alex kernel: [ 9313.056071] Scan in 40M, force to 20M first:3, 1
Feb 29 16:12:07 alex kernel: [ 9314.512081] Scan in 20M, back to 40M
Feb 29 16:12:07 alex kernel: [ 9314.522080] ===>rtl8192se_link_change():ieee->iw_mode is 2
Feb 29 16:12:07 alex kernel: [ 9314.522085] rtl8192_update_cap(): WLAN_CAPABILITY_SHORT_PREAMBLE
Feb 29 16:12:13 alex kernel: [ 9320.176757] RX: IEEE802.1X EAPOL frame!
Feb 29 16:12:13 alex kernel: [ 9320.176904] alg name:CCMP
Feb 29 16:12:13 alex kernel: [ 9320.176921] ===========>set_swcam():EntryNo is 2,KeyIndex is 2,KeyType is 4,is_mesh is 0
Feb 29 16:12:28 alex kernel: [ 9335.615175] rtllib_rx_decrypt: decrypt frame error